From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Fri, 19 Apr 2024 02:47:55 +0200
Subject: Adding upstream version 124.0.1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 layout/reftests/mathml/largeop-1-ref.html          |   0
 layout/reftests/mathml/largeop-1.html              |   0
 .../mathml/mathml-mmultiscript-base-ref.html       |  14 ++
 .../reftests/mathml/mathml-mmultiscript-base.html  |  16 +++
 .../mathml/mathml-mmultiscript-mprescript-ref.html |  15 ++
 .../mathml/mathml-mmultiscript-mprescript.html     |  18 +++
 layout/reftests/mathml/mirror-op-1-ref.html        |  19 +++
 layout/reftests/mathml/mirror-op-1.html            |  14 ++
 layout/reftests/mathml/mirror-op-2-ref.html        |   9 ++
 layout/reftests/mathml/mirror-op-2.html            |   9 ++
 layout/reftests/mathml/mirror-op-3-ref.html        |   9 ++
 layout/reftests/mathml/mirror-op-3.html            |   9 ++
 layout/reftests/mathml/mirror-op-4-ref.html        |   9 ++
 layout/reftests/mathml/mirror-op-4.html            |   9 ++
 layout/reftests/mathml/mmultiscript-align-ref.html |  42 ++++++
 layout/reftests/mathml/mmultiscript-align.html     |  38 +++++
 layout/reftests/mathml/mo-glyph-size-ref.html      |  14 ++
 layout/reftests/mathml/mo-glyph-size.html          |  50 +++++++
 layout/reftests/mathml/mpadded-7-ref.html          |  15 ++
 layout/reftests/mathml/mpadded-7.html              |  16 +++
 layout/reftests/mathml/mpadded-8-ref.html          |  15 ++
 layout/reftests/mathml/mpadded-8.html              |  16 +++
 layout/reftests/mathml/mpadded-9-ref.html          |  15 ++
 layout/reftests/mathml/mpadded-9.html              |  16 +++
 layout/reftests/mathml/mstyle-2-ref.xhtml          | 110 +++++++++++++++
 layout/reftests/mathml/mstyle-2.xhtml              | 113 +++++++++++++++
 layout/reftests/mathml/mstyle-3-ref.xhtml          | 133 ++++++++++++++++++
 layout/reftests/mathml/mstyle-3.xhtml              | 136 ++++++++++++++++++
 layout/reftests/mathml/mstyle-4-ref.xhtml          |  75 ++++++++++
 layout/reftests/mathml/mstyle-4.xhtml              |  78 +++++++++++
 layout/reftests/mathml/multiscripts-1-ref.html     |  71 ++++++++++
 layout/reftests/mathml/multiscripts-1.html         |  71 ++++++++++
 .../munder-mover-align-accent-false-ref.html       | 114 +++++++++++++++
 .../mathml/munder-mover-align-accent-false.html    |  98 +++++++++++++
 .../mathml/munder-mover-align-accent-true-ref.html | 114 +++++++++++++++
 .../mathml/munder-mover-align-accent-true.html     |  98 +++++++++++++
 .../mathml/munderover-align-accent-false-ref.html  | 132 +++++++++++++++++
 .../mathml/munderover-align-accent-false.html      | 104 ++++++++++++++
 .../mathml/munderover-align-accent-true-ref.html   | 132 +++++++++++++++++
 .../mathml/munderover-align-accent-true.html       | 104 ++++++++++++++
 .../mathml/munderover-empty-scripts-ref.html       |  35 +++++
 .../reftests/mathml/munderover-empty-scripts.html  |  32 +++++
 layout/reftests/mathml/overbar-width-1-ref.xhtml   |  26 ++++
 layout/reftests/mathml/overbar-width-1.xhtml       |  25 ++++
 layout/reftests/mathml/radicalbar-1.html           |  48 +++++++
 layout/reftests/mathml/radicalbar-1a.html          |  48 +++++++
 layout/reftests/mathml/radicalbar-1b.html          |  48 +++++++
 layout/reftests/mathml/radicalbar-1c.html          |  48 +++++++
 layout/reftests/mathml/radicalbar-1d.html          |  48 +++++++
 layout/reftests/mathml/radicalbar-2.html           |  47 +++++++
 layout/reftests/mathml/radicalbar-2a.html          |  47 +++++++
 layout/reftests/mathml/radicalbar-2b.html          |  47 +++++++
 layout/reftests/mathml/radicalbar-2c.html          |  47 +++++++
 layout/reftests/mathml/radicalbar-2d.html          |  47 +++++++
 layout/reftests/mathml/radicalbar-3.html           |  47 +++++++
 layout/reftests/mathml/radicalbar-3a.html          |  47 +++++++
 layout/reftests/mathml/radicalbar-3b.html          |  47 +++++++
 layout/reftests/mathml/radicalbar-3c.html          |  47 +++++++
 layout/reftests/mathml/radicalbar-3d.html          |  47 +++++++
 layout/reftests/mathml/reftest.list                |  55 ++++++++
 layout/reftests/mathml/scale-stretchy-1-ref.xhtml  |  26 ++++
 layout/reftests/mathml/scale-stretchy-1.xhtml      |  41 ++++++
 layout/reftests/mathml/scale-stretchy-2-ref.xhtml  |  26 ++++
 layout/reftests/mathml/scale-stretchy-2.xhtml      |  41 ++++++
 layout/reftests/mathml/scale-stretchy-3-ref.xhtml  |  27 ++++
 layout/reftests/mathml/scale-stretchy-3.xhtml      |  43 ++++++
 layout/reftests/mathml/scale-stretchy-4-ref.xhtml  |  27 ++++
 layout/reftests/mathml/scale-stretchy-4.xhtml      |  43 ++++++
 layout/reftests/mathml/scale-stretchy-5-ref.xhtml  |  14 ++
 layout/reftests/mathml/scale-stretchy-5.xhtml      |  14 ++
 .../mathml/scriptlevel-movablelimits-1-ref.html    |  25 ++++
 .../mathml/scriptlevel-movablelimits-1.html        |  25 ++++
 layout/reftests/mathml/semantics-1-ref.xhtml       |  66 +++++++++
 layout/reftests/mathml/semantics-1.xhtml           |  66 +++++++++
 layout/reftests/mathml/semantics-2-ref.html        |  19 +++
 layout/reftests/mathml/semantics-2.html            |  19 +++
 layout/reftests/mathml/semantics-3-ref.html        |  21 +++
 layout/reftests/mathml/semantics-3.html            |  21 +++
 layout/reftests/mathml/semantics-5-ref.html        |  17 +++
 layout/reftests/mathml/semantics-5.html            |  17 +++
 layout/reftests/mathml/stretchy-1-ref.html         |  14 ++
 layout/reftests/mathml/stretchy-1.html             |  14 ++
 layout/reftests/mathml/stretchy-largeop-1-ref.html |  56 ++++++++
 layout/reftests/mathml/stretchy-largeop-1.html     |  81 +++++++++++
 layout/reftests/mathml/stretchy-largeop-2-ref.html | 111 +++++++++++++++
 layout/reftests/mathml/stretchy-largeop-2.html     | 137 ++++++++++++++++++
 layout/reftests/mathml/stretchy-largeop-3-ref.html | 123 ++++++++++++++++
 layout/reftests/mathml/stretchy-largeop-3.html     | 156 +++++++++++++++++++++
 .../mathml/subscript-italic-correction-ref.html    |  36 +++++
 .../mathml/subscript-italic-correction.html        |  61 ++++++++
 layout/reftests/mathml/underbar-width-1-ref.xhtml  |  26 ++++
 layout/reftests/mathml/underbar-width-1.xhtml      |  25 ++++
 92 files changed, 4391 insertions(+)
 create mode 100644 layout/reftests/mathml/largeop-1-ref.html
 create mode 100644 layout/reftests/mathml/largeop-1.html
 create mode 100644 layout/reftests/mathml/mathml-mmultiscript-base-ref.html
 create mode 100644 layout/reftests/mathml/mathml-mmultiscript-base.html
 create mode 100644 layout/reftests/mathml/mathml-mmultiscript-mprescript-ref.html
 create mode 100644 layout/reftests/mathml/mathml-mmultiscript-mprescript.html
 create mode 100644 layout/reftests/mathml/mirror-op-1-ref.html
 create mode 100644 layout/reftests/mathml/mirror-op-1.html
 create mode 100644 layout/reftests/mathml/mirror-op-2-ref.html
 create mode 100644 layout/reftests/mathml/mirror-op-2.html
 create mode 100644 layout/reftests/mathml/mirror-op-3-ref.html
 create mode 100644 layout/reftests/mathml/mirror-op-3.html
 create mode 100644 layout/reftests/mathml/mirror-op-4-ref.html
 create mode 100644 layout/reftests/mathml/mirror-op-4.html
 create mode 100644 layout/reftests/mathml/mmultiscript-align-ref.html
 create mode 100644 layout/reftests/mathml/mmultiscript-align.html
 create mode 100644 layout/reftests/mathml/mo-glyph-size-ref.html
 create mode 100644 layout/reftests/mathml/mo-glyph-size.html
 create mode 100644 layout/reftests/mathml/mpadded-7-ref.html
 create mode 100644 layout/reftests/mathml/mpadded-7.html
 create mode 100644 layout/reftests/mathml/mpadded-8-ref.html
 create mode 100644 layout/reftests/mathml/mpadded-8.html
 create mode 100644 layout/reftests/mathml/mpadded-9-ref.html
 create mode 100644 layout/reftests/mathml/mpadded-9.html
 create mode 100644 layout/reftests/mathml/mstyle-2-ref.xhtml
 create mode 100644 layout/reftests/mathml/mstyle-2.xhtml
 create mode 100644 layout/reftests/mathml/mstyle-3-ref.xhtml
 create mode 100644 layout/reftests/mathml/mstyle-3.xhtml
 create mode 100644 layout/reftests/mathml/mstyle-4-ref.xhtml
 create mode 100644 layout/reftests/mathml/mstyle-4.xhtml
 create mode 100644 layout/reftests/mathml/multiscripts-1-ref.html
 create mode 100644 layout/reftests/mathml/multiscripts-1.html
 create mode 100644 layout/reftests/mathml/munder-mover-align-accent-false-ref.html
 create mode 100644 layout/reftests/mathml/munder-mover-align-accent-false.html
 create mode 100644 layout/reftests/mathml/munder-mover-align-accent-true-ref.html
 create mode 100644 layout/reftests/mathml/munder-mover-align-accent-true.html
 create mode 100644 layout/reftests/mathml/munderover-align-accent-false-ref.html
 create mode 100644 layout/reftests/mathml/munderover-align-accent-false.html
 create mode 100644 layout/reftests/mathml/munderover-align-accent-true-ref.html
 create mode 100644 layout/reftests/mathml/munderover-align-accent-true.html
 create mode 100644 layout/reftests/mathml/munderover-empty-scripts-ref.html
 create mode 100644 layout/reftests/mathml/munderover-empty-scripts.html
 create mode 100644 layout/reftests/mathml/overbar-width-1-ref.xhtml
 create mode 100644 layout/reftests/mathml/overbar-width-1.xhtml
 create mode 100644 layout/reftests/mathml/radicalbar-1.html
 create mode 100644 layout/reftests/mathml/radicalbar-1a.html
 create mode 100644 layout/reftests/mathml/radicalbar-1b.html
 create mode 100644 layout/reftests/mathml/radicalbar-1c.html
 create mode 100644 layout/reftests/mathml/radicalbar-1d.html
 create mode 100644 layout/reftests/mathml/radicalbar-2.html
 create mode 100644 layout/reftests/mathml/radicalbar-2a.html
 create mode 100644 layout/reftests/mathml/radicalbar-2b.html
 create mode 100644 layout/reftests/mathml/radicalbar-2c.html
 create mode 100644 layout/reftests/mathml/radicalbar-2d.html
 create mode 100644 layout/reftests/mathml/radicalbar-3.html
 create mode 100644 layout/reftests/mathml/radicalbar-3a.html
 create mode 100644 layout/reftests/mathml/radicalbar-3b.html
 create mode 100644 layout/reftests/mathml/radicalbar-3c.html
 create mode 100644 layout/reftests/mathml/radicalbar-3d.html
 create mode 100644 layout/reftests/mathml/reftest.list
 create mode 100644 layout/reftests/mathml/scale-stretchy-1-ref.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-1.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-2-ref.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-2.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-3-ref.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-3.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-4-ref.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-4.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-5-ref.xhtml
 create mode 100644 layout/reftests/mathml/scale-stretchy-5.xhtml
 create mode 100644 layout/reftests/mathml/scriptlevel-movablelimits-1-ref.html
 create mode 100644 layout/reftests/mathml/scriptlevel-movablelimits-1.html
 create mode 100644 layout/reftests/mathml/semantics-1-ref.xhtml
 create mode 100644 layout/reftests/mathml/semantics-1.xhtml
 create mode 100644 layout/reftests/mathml/semantics-2-ref.html
 create mode 100644 layout/reftests/mathml/semantics-2.html
 create mode 100644 layout/reftests/mathml/semantics-3-ref.html
 create mode 100644 layout/reftests/mathml/semantics-3.html
 create mode 100644 layout/reftests/mathml/semantics-5-ref.html
 create mode 100644 layout/reftests/mathml/semantics-5.html
 create mode 100644 layout/reftests/mathml/stretchy-1-ref.html
 create mode 100644 layout/reftests/mathml/stretchy-1.html
 create mode 100644 layout/reftests/mathml/stretchy-largeop-1-ref.html
 create mode 100644 layout/reftests/mathml/stretchy-largeop-1.html
 create mode 100644 layout/reftests/mathml/stretchy-largeop-2-ref.html
 create mode 100644 layout/reftests/mathml/stretchy-largeop-2.html
 create mode 100644 layout/reftests/mathml/stretchy-largeop-3-ref.html
 create mode 100644 layout/reftests/mathml/stretchy-largeop-3.html
 create mode 100644 layout/reftests/mathml/subscript-italic-correction-ref.html
 create mode 100644 layout/reftests/mathml/subscript-italic-correction.html
 create mode 100644 layout/reftests/mathml/underbar-width-1-ref.xhtml
 create mode 100644 layout/reftests/mathml/underbar-width-1.xhtml

(limited to 'layout/reftests/mathml')

diff --git a/layout/reftests/mathml/largeop-1-ref.html b/layout/reftests/mathml/largeop-1-ref.html
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/layout/reftests/mathml/largeop-1.html b/layout/reftests/mathml/largeop-1.html
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/layout/reftests/mathml/mathml-mmultiscript-base-ref.html b/layout/reftests/mathml/mathml-mmultiscript-base-ref.html
new file mode 100644
index 0000000000..45f43e9f9b
--- /dev/null
+++ b/layout/reftests/mathml/mathml-mmultiscript-base-ref.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<title>mmultiscript with only base</title>
+	</head>
+	
+	<body>
+		<math>
+			<mmultiscripts>
+			<mtext>base</mtext>
+			</mmultiscripts>
+		</math>
+	</body>
+</html>
diff --git a/layout/reftests/mathml/mathml-mmultiscript-base.html b/layout/reftests/mathml/mathml-mmultiscript-base.html
new file mode 100644
index 0000000000..f2832df479
--- /dev/null
+++ b/layout/reftests/mathml/mathml-mmultiscript-base.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<title>mmultiscript with only base and none as placeholder</title>
+	</head>
+
+	<body>
+		<math> 
+			<mmultiscripts>
+				<mtext>base</mtext>
+				<none/>
+				<none/>
+			</mmultiscripts>
+		</math>
+	</body>
+</html>
diff --git a/layout/reftests/mathml/mathml-mmultiscript-mprescript-ref.html b/layout/reftests/mathml/mathml-mmultiscript-mprescript-ref.html
new file mode 100644
index 0000000000..b30e7fb976
--- /dev/null
+++ b/layout/reftests/mathml/mathml-mmultiscript-mprescript-ref.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<title>mmultiscript with mprescripts without none</title>
+	</head>
+
+	<body>
+		<math> 
+			<mmultiscripts>
+				<mtext>base</mtext>
+				<mprescripts/>
+			</mmultiscripts>
+		</math>
+	</body>
+</html>
diff --git a/layout/reftests/mathml/mathml-mmultiscript-mprescript.html b/layout/reftests/mathml/mathml-mmultiscript-mprescript.html
new file mode 100644
index 0000000000..5bc0b5a5ad
--- /dev/null
+++ b/layout/reftests/mathml/mathml-mmultiscript-mprescript.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<title>mmultiscript with mprescripts with none as placeholders</title>
+	</head>
+	
+	<body>
+		<math>
+			<mmultiscripts>
+				<mtext>base</mtext>
+				<none/>
+				<none/>
+				<mprescripts/>
+			</mmultiscripts>
+
+		</math>
+	</body>
+</html>
diff --git a/layout/reftests/mathml/mirror-op-1-ref.html b/layout/reftests/mathml/mirror-op-1-ref.html
new file mode 100644
index 0000000000..d7515156c3
--- /dev/null
+++ b/layout/reftests/mathml/mirror-op-1-ref.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test mirror op</title></head>
+  <style type="text/css">
+    mo {
+      transform: scaleX(-1.0);
+    }
+  </style>
+  <body>
+
+    <p><math><mo>(</mo></math></p>
+    <p><math><mo>)</mo></math></p>
+    <p><math><mo>[</mo></math></p>
+    <p><math><mo>]</mo></math></p>
+    <p><math><mo>{</mo></math></p>
+    <p><math><mo>}</mo></math></p>
+    
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mirror-op-1.html b/layout/reftests/mathml/mirror-op-1.html
new file mode 100644
index 0000000000..bb59e16c23
--- /dev/null
+++ b/layout/reftests/mathml/mirror-op-1.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test mirror op</title></head>
+  <body>
+
+    <p><math dir="rtl"><mo>(</mo></math></p>
+    <p><math dir="rtl"><mo>)</mo></math></p>
+    <p><math dir="rtl"><mo>[</mo></math></p>
+    <p><math dir="rtl"><mo>]</mo></math></p>
+    <p><math dir="rtl"><mo>{</mo></math></p>
+    <p><math dir="rtl"><mo>}</mo></math></p>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mirror-op-2-ref.html b/layout/reftests/mathml/mirror-op-2-ref.html
new file mode 100644
index 0000000000..c67710cca6
--- /dev/null
+++ b/layout/reftests/mathml/mirror-op-2-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test mirror op</title></head>
+  <body>
+
+    <p><math display="block"><mo>&#x2211;</mo></math></p>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mirror-op-2.html b/layout/reftests/mathml/mirror-op-2.html
new file mode 100644
index 0000000000..5db6819cfe
--- /dev/null
+++ b/layout/reftests/mathml/mirror-op-2.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test mirror op</title></head>
+  <body>
+
+    <p><math display="block" dir="rtl"><mo>&#x2211;</mo></math></p>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mirror-op-3-ref.html b/layout/reftests/mathml/mirror-op-3-ref.html
new file mode 100644
index 0000000000..fc3a183ef3
--- /dev/null
+++ b/layout/reftests/mathml/mirror-op-3-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test mirror op</title></head>
+  <body>
+
+    <p><math display="block"><mo>&#x221A;</mo></math></p>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mirror-op-3.html b/layout/reftests/mathml/mirror-op-3.html
new file mode 100644
index 0000000000..501af10926
--- /dev/null
+++ b/layout/reftests/mathml/mirror-op-3.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test mirror op</title></head>
+  <body>
+
+    <p><math display="block" dir="rtl"><mo>&#x221A;</mo></math></p>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mirror-op-4-ref.html b/layout/reftests/mathml/mirror-op-4-ref.html
new file mode 100644
index 0000000000..6c39a47a33
--- /dev/null
+++ b/layout/reftests/mathml/mirror-op-4-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test mirror op</title></head>
+  <body>
+
+    <p><math display="block"><mo>&#x222B;</mo></math></p>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mirror-op-4.html b/layout/reftests/mathml/mirror-op-4.html
new file mode 100644
index 0000000000..ba1acf89f7
--- /dev/null
+++ b/layout/reftests/mathml/mirror-op-4.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test mirror op</title></head>
+  <body>
+
+    <p><math display="block" dir="rtl"><mo>&#x222B;</mo></math></p>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mmultiscript-align-ref.html b/layout/reftests/mathml/mmultiscript-align-ref.html
new file mode 100644
index 0000000000..337852837f
--- /dev/null
+++ b/layout/reftests/mathml/mmultiscript-align-ref.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>alignment of mmultiscript sub/superscripts</title>
+  </head>
+
+  <body>
+    <math>
+      <mmultiscripts>
+        <mspace width="50px" height="50px" mathbackground="red"/>
+        <mrow>
+          <mspace width="50px" height="10px" mathbackground="blue"/>
+          <mspace width="50px" height="10px"/>
+        </mrow>
+        <mspace width="100px" height="10px" mathbackground="green"/>
+        <mprescripts/>
+        <mrow>
+          <mspace width="50px" height="10px"/>
+          <mspace width="50px" height="10px" mathbackground="blue"/>
+        </mrow>
+        <mspace width="100px" height="10px" mathbackground="green"/>
+      </mmultiscripts>
+    </math>
+    <br/>
+    <math>
+      <mmultiscripts>
+        <mspace width="50px" height="50px" mathbackground="red"/>
+        <mspace width="100px" height="10px" mathbackground="green"/>
+        <mrow>
+          <mspace width="50px" height="10px" mathbackground="blue"/>
+          <mspace width="50px" height="10px"/>
+        </mrow>
+        <mprescripts/>
+        <mspace width="100px" height="10px" mathbackground="green"/>
+        <mrow>
+          <mspace width="50px" height="10px"/>
+          <mspace width="50px" height="10px" mathbackground="blue"/>
+        </mrow>
+      </mmultiscripts>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mmultiscript-align.html b/layout/reftests/mathml/mmultiscript-align.html
new file mode 100644
index 0000000000..44fb713a34
--- /dev/null
+++ b/layout/reftests/mathml/mmultiscript-align.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>alignment of mmultiscript sub/superscripts</title>
+  </head>
+
+  <body>
+    <math>
+      <mmultiscripts>
+        <mspace width="50px" height="50px" mathbackground="red"/>
+        <mrow>
+          <mspace width="50px" height="10px" mathbackground="blue"/>
+        </mrow>
+        <mspace width="100px" height="10px" mathbackground="green"/>
+        <mprescripts/>
+        <mrow>
+          <mspace width="50px" height="10px" mathbackground="blue"/>
+        </mrow>
+        <mspace width="100px" height="10px" mathbackground="green"/>
+      </mmultiscripts>
+    </math>
+    <br/>
+    <math>
+      <mmultiscripts>
+        <mspace width="50px" height="50px" mathbackground="red"/>
+        <mspace width="100px" height="10px" mathbackground="green"/>
+        <mrow>
+          <mspace width="50px" height="10px" mathbackground="blue"/>
+        </mrow>
+        <mprescripts/>
+        <mspace width="100px" height="10px" mathbackground="green"/>
+        <mrow>
+          <mspace width="50px" height="10px" mathbackground="blue"/>
+        </mrow>
+      </mmultiscripts>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mo-glyph-size-ref.html b/layout/reftests/mathml/mo-glyph-size-ref.html
new file mode 100644
index 0000000000..e4dd43747e
--- /dev/null
+++ b/layout/reftests/mathml/mo-glyph-size-ref.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="UTF-8">
+</head>
+<body>
+<!-- Bug 1219068 -->
+
+<div id="hider"
+     style="position:absolute; top:0; left:0; background-color:green;
+            height:1em; width:100%; z-index:1; padding-top:5px;
+            padding-bottom:5px;" />
+</body>
+</html>
diff --git a/layout/reftests/mathml/mo-glyph-size.html b/layout/reftests/mathml/mo-glyph-size.html
new file mode 100644
index 0000000000..c0cc726daf
--- /dev/null
+++ b/layout/reftests/mathml/mo-glyph-size.html
@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+<head>
+<meta charset="UTF-8">
+</head>
+<body>
+<!-- Bug 1219068 -->
+
+<math style="position:absolute; top: 0; font-size:1em;  z-index: 0;" display="block">
+<mrow>
+  <mo>|</mo>
+  <mrow>
+    <mi>f</mi>
+    <mrow>
+      <mn>(</mn>
+      <mi>x</mi>
+      <mn>)</mn>
+    </mrow>
+    <mn>-</mn>
+    <mrow>
+      <mi>f</mi>
+      <mrow>
+        <mn>(</mn>
+        <msub>
+          <mi>x</mi>
+          <mn>0</mn>
+        </msub>
+        <mn>)</mn>
+      </mrow>
+    </mrow>
+  </mrow>
+  <mo>|</mo>
+</mrow>
+</math>
+<div id="hider"
+     style="position:absolute; top:0; left:0; background-color:green;
+            height:1em; width:100%; z-index:1; padding-top:5px;
+            padding-bottom:5px; visibility:hidden" />
+  <script>
+    function obscureMathML() {
+      var hider = document.getElementById("hider");
+      hider.style.visibility="visible";
+      // The math should now be completely obscured
+
+      document.documentElement.removeAttribute("class");
+    }
+    window.addEventListener("MozReftestInvalidate", obscureMathML);
+  </script>
+</body>
+</html>
diff --git a/layout/reftests/mathml/mpadded-7-ref.html b/layout/reftests/mathml/mpadded-7-ref.html
new file mode 100644
index 0000000000..50f14246ee
--- /dev/null
+++ b/layout/reftests/mathml/mpadded-7-ref.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Test mpadded</title>
+  </head>
+  <body>
+    <math>
+      <mpadded mathbackground="red" height="100height" depth="0">
+        <mphantom>
+          <mtext>&#x1D687;<!-- Mathematical Monospace Capital X --></mtext>
+        </mphantom>
+      </mpadded>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mpadded-7.html b/layout/reftests/mathml/mpadded-7.html
new file mode 100644
index 0000000000..94d51b5845
--- /dev/null
+++ b/layout/reftests/mathml/mpadded-7.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Test mpadded</title>
+  </head>
+  <body>
+    <math>
+      <!--height in term of height should not depend on the characters-->
+      <mpadded mathbackground="red" height="100height" depth="0">
+        <mphantom>
+          <mtext>&#x1D692;<!-- Mathematical Monospace Small I --></mtext>
+        </mphantom>
+      </mpadded>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mpadded-8-ref.html b/layout/reftests/mathml/mpadded-8-ref.html
new file mode 100644
index 0000000000..e01e6498f2
--- /dev/null
+++ b/layout/reftests/mathml/mpadded-8-ref.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Test mpadded</title>
+  </head>
+  <body>
+    <math>
+      <mpadded mathbackground="red" height="100width" depth="0">
+        <mphantom>
+          <mtext>&#x1D687;<!-- Mathematical Monospace Capital X --></mtext>
+        </mphantom>
+      </mpadded>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mpadded-8.html b/layout/reftests/mathml/mpadded-8.html
new file mode 100644
index 0000000000..4f203d4225
--- /dev/null
+++ b/layout/reftests/mathml/mpadded-8.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Test mpadded</title>
+  </head>
+  <body>
+    <math>
+      <!--height in term of width should not depend on the characters-->
+      <mpadded mathbackground="red" height="100width" depth="0">
+        <mphantom>
+          <mtext>&#x1D692;<!-- Mathematical Monospace Small I --></mtext>
+        </mphantom>
+      </mpadded>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mpadded-9-ref.html b/layout/reftests/mathml/mpadded-9-ref.html
new file mode 100644
index 0000000000..e2a4943edd
--- /dev/null
+++ b/layout/reftests/mathml/mpadded-9-ref.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Test mpadded</title>
+  </head>
+  <body>
+    <math>
+      <mpadded mathbackground="red" width="100width">
+        <mphantom>
+          <mtext>&#x1D687;<!-- Mathematical Monospace Capital X --></mtext>
+        </mphantom>
+      </mpadded>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mpadded-9.html b/layout/reftests/mathml/mpadded-9.html
new file mode 100644
index 0000000000..2b86721f50
--- /dev/null
+++ b/layout/reftests/mathml/mpadded-9.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Test mpadded</title>
+  </head>
+  <body>
+    <math>
+      <!--with fixed width, height + depth should not depend on the characters-->
+      <mpadded mathbackground="red" width="100width">
+        <mphantom>
+          <mtext>&#x1D692;<!-- Mathematical Monospace Small I --></mtext>
+        </mphantom>
+      </mpadded>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/mstyle-2-ref.xhtml b/layout/reftests/mathml/mstyle-2-ref.xhtml
new file mode 100644
index 0000000000..a8843780cb
--- /dev/null
+++ b/layout/reftests/mathml/mstyle-2-ref.xhtml
@@ -0,0 +1,110 @@
+<?xml version="1.0" encoding="us-ascii"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta http-equiv="content-type"
+  content="application/xhtml+xml; charset=us-ascii" />
+  <title>Test mstyle</title>
+  <style type="text/css">
+    table { width: 100%;  border-collapse: collapse; }
+    td { border: solid black 1px; }
+  </style>
+</head>
+
+<body>
+
+<table>
+  <tbody>
+    <tr>
+      <td>mpadded: width</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mtext>_</mtext>
+            <mpadded/>
+            <mtext>_</mtext>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mpadded: lspace</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mtext>_</mtext>
+            <mpadded/>
+            <mtext>_</mtext>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mpadded: height</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <msup>
+              <mrow>
+                <mtext>_</mtext>
+                <mpadded/>
+                <mtext>_</mtext>
+              </mrow>
+              <mtext>_</mtext>
+            </msup>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mpadded: depth</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <msub>
+              <mrow>
+                <mtext>_</mtext>
+                <mpadded/>
+                <mtext>_</mtext>
+              </mrow>
+              <mtext>_</mtext>
+            </msub>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mspace: width</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mtext>_</mtext>
+            <mspace/>
+            <mtext>_</mtext>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mspace: height</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <msup>
+              <mrow>
+                <mtext>_</mtext>
+                <mspace/>
+                <mtext>_</mtext>
+              </mrow>
+              <mtext>_</mtext>
+            </msup>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mspace: depth</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <msub>
+              <mrow>
+                <mtext>_</mtext>
+                <mspace/>
+                <mtext>_</mtext>
+              </mrow>
+              <mtext>_</mtext>
+            </msub>
+          </mstyle>
+        </math></td>
+    </tr>
+  </tbody>
+</table>
+</body>
+</html>
diff --git a/layout/reftests/mathml/mstyle-2.xhtml b/layout/reftests/mathml/mstyle-2.xhtml
new file mode 100644
index 0000000000..f11f3ad8cd
--- /dev/null
+++ b/layout/reftests/mathml/mstyle-2.xhtml
@@ -0,0 +1,113 @@
+<?xml version="1.0" encoding="us-ascii"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta http-equiv="content-type"
+  content="application/xhtml+xml; charset=us-ascii" />
+  <title>Test mstyle</title>
+  <style type="text/css">
+    table { width: 100%;  border-collapse: collapse; }
+    td { border: solid black 1px; }
+  </style>
+</head>
+
+<body>
+
+<!-- The attributes below should no longer have effect on <mstyle>/<math>
+     elements. See bug 838509 -->
+
+<table>
+  <tbody>
+    <tr>
+      <td>mpadded: width</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" width="1em">
+          <mstyle width="1em">
+            <mtext>_</mtext>
+            <mpadded/>
+            <mtext>_</mtext>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mpadded: lspace</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" lspace="1em">
+          <mstyle lspace="1em">
+            <mtext>_</mtext>
+            <mpadded/>
+            <mtext>_</mtext>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mpadded: height</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" height="1em">
+          <mstyle height="1em">
+            <msup>
+              <mrow>
+                <mtext>_</mtext>
+                <mpadded/>
+                <mtext>_</mtext>
+              </mrow>
+              <mtext>_</mtext>
+            </msup>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mpadded: depth</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" depth="1em">
+          <mstyle depth="1em">
+            <msub>
+              <mrow>
+                <mtext>_</mtext>
+                <mpadded/>
+                <mtext>_</mtext>
+              </mrow>
+              <mtext>_</mtext>
+            </msub>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mspace: width</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" width="1em">
+          <mstyle width="1em">
+            <mtext>_</mtext>
+            <mspace/>
+            <mtext>_</mtext>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mspace: height</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" height="1em">
+          <mstyle height="1em">
+            <msup>
+              <mrow>
+                <mtext>_</mtext>
+                <mspace/>
+                <mtext>_</mtext>
+              </mrow>
+              <mtext>_</mtext>
+            </msup>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mspace: depth</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" depth="1em">
+          <mstyle depth="1em">
+            <msub>
+              <mrow>
+                <mtext>_</mtext>
+                <mspace/>
+                <mtext>_</mtext>
+              </mrow>
+              <mtext>_</mtext>
+            </msub>
+          </mstyle>
+        </math></td>
+    </tr>
+  </tbody>
+</table>
+</body>
+</html>
diff --git a/layout/reftests/mathml/mstyle-3-ref.xhtml b/layout/reftests/mathml/mstyle-3-ref.xhtml
new file mode 100644
index 0000000000..66c03f89ad
--- /dev/null
+++ b/layout/reftests/mathml/mstyle-3-ref.xhtml
@@ -0,0 +1,133 @@
+<?xml version="1.0" encoding="us-ascii"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta http-equiv="content-type"
+  content="application/xhtml+xml; charset=us-ascii" />
+  <title>Test mstyle</title>
+  <style type="text/css">
+    table { width: 100%;  border-collapse: collapse; }
+    td { border: solid black 1px; }
+  </style>
+</head>
+
+<body>
+
+<table>
+  <tbody>
+    <tr>
+      <td>mo: form</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mrow>
+              <!-- We assume that the infix/postfix forms of _ do -->
+              <!-- not have the same lspace/rspace values in the operator dictionary -->
+              <mtext>_</mtext>
+              <mo>_</mo>
+              <mtext>_</mtext>
+            </mrow>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: lspace, rspace</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mrow>
+              <!-- We assume that the infix form of _ has -->
+              <!-- nonzero lspace/rspace values in the operator dictionary -->
+              <mtext>_</mtext>
+              <mo>_</mo>
+              <mtext>_</mtext>
+            </mrow>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: stretchy</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mover>
+              <!-- We assume that the arrow has stretchy=true in the operator dictionary -->
+              <mtext>abcd</mtext>
+              <mo>&#x2192;</mo>
+            </mover>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: accent</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mover>
+              <!-- We assume &#x23de; has accent=true in the operator dictionary -->
+              <mrow>
+                <mi>x</mi>
+                <mo>+</mo>
+                <mi>y</mi>
+                <mo>+</mo>
+                <mi>z</mi>
+              </mrow>
+              <mo>&#x23de;</mo>
+            </mover>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: maxsize</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mo>(</mo>
+            <mspace height="3em"/>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: minsize</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mo>(</mo>
+            <mspace height="1em"/>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: symmetric</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <!-- We assume that ( has symmetric=true in the operator dictionary -->
+          <mstyle>
+            <mtext>_</mtext>
+            <mo minsize="200%">(</mo>
+            <mtext>_</mtext>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: movablelimits</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <!-- We assume that &#x2211; has movablelimits=true in the operator dictionary -->
+          <mstyle>
+            <munderover>
+              <mo>&#x2211;</mo>
+              <mi>a</mi>
+              <mi>b</mi>
+            </munderover>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: largeop</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+          <!-- We assume that &#x2211; has largeop=true in the operator dictionary -->
+          <mstyle>
+            <mo>&#x2211;</mo>
+          </mstyle>
+        </math></td>
+    </tr>
+    <!-- 
+            fence: This attribute generally has no direct effect on the visual rendering.
+            separator: This attribute generally has no direct effect on the visual rendering.
+      -->
+  </tbody>
+</table>
+</body>
+</html>
diff --git a/layout/reftests/mathml/mstyle-3.xhtml b/layout/reftests/mathml/mstyle-3.xhtml
new file mode 100644
index 0000000000..4b395d3942
--- /dev/null
+++ b/layout/reftests/mathml/mstyle-3.xhtml
@@ -0,0 +1,136 @@
+<?xml version="1.0" encoding="us-ascii"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta http-equiv="content-type"
+  content="application/xhtml+xml; charset=us-ascii" />
+  <title>Test mstyle</title>
+  <style type="text/css">
+    table { width: 100%;  border-collapse: collapse; }
+    td { border: solid black 1px; }
+  </style>
+</head>
+
+<body>
+
+<!-- The attributes below (except math@display) should no longer have effect on
+     <mstyle>/<math> elements. See bug 838509 -->
+
+<table>
+  <tbody>
+    <tr>
+      <td>mo: form</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" form="postfix">
+          <mstyle form="postfix">
+            <mrow>
+              <!-- We assume that the infix/postfix forms of _ do -->
+              <!-- not have the same lspace/rspace values in the operator dictionary -->
+              <mtext>_</mtext>
+              <mo>_</mo>
+              <mtext>_</mtext>
+            </mrow>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: lspace, rspace</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" lspace="0" rspace="0">
+          <mstyle lspace="0" rspace="0">
+            <mrow>
+              <!-- We assume that the infix form of _ has -->
+              <!-- nonzero lspace/rspace values in the operator dictionary -->
+              <mtext>_</mtext>
+              <mo>_</mo>
+              <mtext>_</mtext>
+            </mrow>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: stretchy</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" stretchy="false">
+          <mstyle stretchy="false">
+            <mover>
+              <!-- We assume that the arrow has stretchy=true in the operator dictionary -->
+              <mtext>abcd</mtext>
+              <mo>&#x2192;</mo>
+            </mover>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: accent</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" accent="false">
+          <mstyle accent="false">
+            <mover>
+              <!-- We assume &#x23de; has accent=true in the operator dictionary -->
+              <mrow>
+                <mi>x</mi>
+                <mo>+</mo>
+                <mi>y</mi>
+                <mo>+</mo>
+                <mi>z</mi>
+              </mrow>
+              <mo>&#x23de;</mo>
+            </mover>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: maxsize</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" maxsize="100%">
+          <mstyle maxsize="100%">
+            <mo>(</mo>
+            <mspace height="3em"/>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: minsize</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" minsize="300%">
+          <mstyle minsize="300%">
+            <mo>(</mo>
+            <mspace height="1em"/>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: symmetric</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" symmetric="false">
+          <!-- We assume that ( has symmetric=true in the operator dictionary -->
+          <mstyle symmetric="false">
+            <mtext>_</mtext>
+            <mo minsize="200%">(</mo>
+            <mtext>_</mtext>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: movablelimits</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" movablelimits="false">
+          <!-- We assume that &#x2211; has movablelimits=true in the operator dictionary -->
+          <mstyle movablelimits="false">
+            <munderover>
+              <mo>&#x2211;</mo>
+              <mi>a</mi>
+              <mi>b</mi>
+            </munderover>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>mo: largeop</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" display="block" largeop="false">
+          <!-- We assume that &#x2211; has largeop=true in the operator dictionary -->
+          <mstyle largeop="false">
+            <mo>&#x2211;</mo>
+          </mstyle>
+        </math></td>
+    </tr>
+    <!-- 
+            fence: This attribute generally has no direct effect on the visual rendering.
+            separator: This attribute generally has no direct effect on the visual rendering.
+      -->
+  </tbody>
+</table>
+</body>
+</html>
diff --git a/layout/reftests/mathml/mstyle-4-ref.xhtml b/layout/reftests/mathml/mstyle-4-ref.xhtml
new file mode 100644
index 0000000000..e82876083e
--- /dev/null
+++ b/layout/reftests/mathml/mstyle-4-ref.xhtml
@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="us-ascii"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta http-equiv="content-type"
+  content="application/xhtml+xml; charset=us-ascii" />
+  <title>Test mstyle</title>
+  <style type="text/css">
+    table { width: 100%;  border-collapse: collapse; }
+    td { border: solid black 1px; }
+  </style>
+</head>
+
+<body>
+
+<table>
+  <tbody>
+    <tr>
+      <td>mover: accent</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <mover>
+              <!-- We assume &#x23de; is accent in the operator dictionary -->
+              <mrow>
+                <mi>x</mi>
+                <mo>+</mo>
+                <mi>y</mi>
+                <mo>+</mo>
+                <mi>z</mi>
+              </mrow>
+              <mo>&#x23de;</mo>
+            </mover>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>munder: accentunder</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <munder>
+              <!-- We assume &#x23df; is accent in the operator dictionary -->
+              <mrow>
+                <mi>x</mi>
+                <mo>+</mo>
+                <mi>y</mi>
+                <mo>+</mo>
+                <mi>z</mi>
+              </mrow>
+              <mo>&#x23df;</mo>
+            </munder>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>munderover: accent, accentunder</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML">
+          <mstyle>
+            <munderover>
+              <!-- We assume &#x23de; and &#x23df; are accents in the operator dictionary -->
+              <mrow>
+                <mi>x</mi>
+                <mo>+</mo>
+                <mi>y</mi>
+                <mo>+</mo>
+                <mi>z</mi>
+              </mrow>
+              <mo>&#x23df;</mo>
+              <mo>&#x23de;</mo>
+            </munderover>
+          </mstyle>
+        </math></td>
+    </tr>
+  </tbody>
+</table>
+</body>
+</html>
diff --git a/layout/reftests/mathml/mstyle-4.xhtml b/layout/reftests/mathml/mstyle-4.xhtml
new file mode 100644
index 0000000000..e934977557
--- /dev/null
+++ b/layout/reftests/mathml/mstyle-4.xhtml
@@ -0,0 +1,78 @@
+<?xml version="1.0" encoding="us-ascii"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta http-equiv="content-type"
+  content="application/xhtml+xml; charset=us-ascii" />
+  <title>Test mstyle</title>
+  <style type="text/css">
+    table { width: 100%;  border-collapse: collapse; }
+    td { border: solid black 1px; }
+  </style>
+</head>
+
+<body>
+
+<!-- The attributes below should no longer have effect on <mstyle>/<math>
+     elements. See bug 838509 -->
+
+<table>
+  <tbody>
+    <tr>
+      <td>mover: accent</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" accent="false">
+          <mstyle accent="false">
+            <mover>
+              <!-- We assume &#x23de; is accent in the operator dictionary -->
+              <mrow>
+                <mi>x</mi>
+                <mo>+</mo>
+                <mi>y</mi>
+                <mo>+</mo>
+                <mi>z</mi>
+              </mrow>
+              <mo>&#x23de;</mo>
+            </mover>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>munder: accentunder</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" accentunder="false">
+          <mstyle accentunder="false">
+            <munder>
+              <!-- We assume &#x23df; is accent in the operator dictionary -->
+              <mrow>
+                <mi>x</mi>
+                <mo>+</mo>
+                <mi>y</mi>
+                <mo>+</mo>
+                <mi>z</mi>
+              </mrow>
+              <mo>&#x23df;</mo>
+            </munder>
+          </mstyle>
+        </math></td>
+    </tr>
+    <tr>
+      <td>munderover: accent, accentunder</td>
+      <td><math xmlns="http://www.w3.org/1998/Math/MathML" accent="false" accentunder="false">
+          <mstyle accent="false" accentunder="false">
+            <munderover>
+              <!-- We assume &#x23de; and &#x23df; are accents in the operator dictionary -->
+              <mrow>
+                <mi>x</mi>
+                <mo>+</mo>
+                <mi>y</mi>
+                <mo>+</mo>
+                <mi>z</mi>
+              </mrow>
+              <mo>&#x23df;</mo>
+              <mo>&#x23de;</mo>
+            </munderover>
+          </mstyle>
+        </math></td>
+    </tr>
+  </tbody>
+</table>
+</body>
+</html>
diff --git a/layout/reftests/mathml/multiscripts-1-ref.html b/layout/reftests/mathml/multiscripts-1-ref.html
new file mode 100644
index 0000000000..2fcc142503
--- /dev/null
+++ b/layout/reftests/mathml/multiscripts-1-ref.html
@@ -0,0 +1,71 @@
+<!DOCTYPE html>
+<html><head>
+<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"><title>Comparison of script elements</title></head>
+  <body>
+    msubsup:
+    <math>
+      <mmultiscripts style="background: red;">
+	<mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+	<mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+	<mtext style="background-color: rgba(0, 255, 0, 0.4);">ccc</mtext>
+      </mmultiscripts>
+    </math>
+
+    <br><br>
+
+    msubsup:
+    <math>
+      <mmultiscripts style="background: red;">
+	<mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+	<mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+        <none/>
+      </mmultiscripts>
+    </math>
+
+    <br><br>
+
+    msup / msubsup:
+    <math>
+      <mmultiscripts style="background: red;">
+	<mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <none/>
+	<mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+      </mmultiscripts>
+    </math>
+
+    <math>
+      <mmultiscripts style="background: red;">
+	<mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <none/>
+	<mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+      </mmultiscripts>
+    </math>
+
+    <br><br>
+
+
+    mrow / msub:
+    <math>
+      <mrow style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+      </mrow>
+    </math>
+
+    <math>
+      <mrow style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+      </mrow>
+    </math>
+
+    <br><br>
+
+    msupsub:
+    <math>
+      <mmultiscripts style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <none />
+        <none />
+      </mmultiscripts>
+    </math>
+
+</body></html>
diff --git a/layout/reftests/mathml/multiscripts-1.html b/layout/reftests/mathml/multiscripts-1.html
new file mode 100644
index 0000000000..fa45ff3699
--- /dev/null
+++ b/layout/reftests/mathml/multiscripts-1.html
@@ -0,0 +1,71 @@
+<!DOCTYPE html>
+<html><head>
+<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"><title>Comparison of script elements</title></head>
+  <body>
+    msubsup:
+    <math>
+      <msubsup style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">ccc</mtext>
+      </msubsup>
+    </math>
+
+    <br><br>
+
+    <!-- Different rules apply to msub, so it won't provide equivalent output -->
+    msubsup:
+    <math>
+      <msubsup style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+        <mrow></mrow>
+      </msubsup>
+    </math>
+
+    <br><br>
+
+    msup / msubsup:
+    <math>
+      <msup style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+      </msup>
+    </math>
+
+    <math>
+      <msubsup style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mrow></mrow>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+      </msubsup>
+    </math>
+
+    <br><br>
+
+    mrow / msub:
+    <math>
+      <mrow style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+      </mrow>
+    </math>
+
+    <math>
+      <msub style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mrow></mrow>
+      </msub>
+    </math>
+
+    <br><br>
+
+    msupsub:
+    <math>
+      <msubsup style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mrow></mrow>
+        <mrow></mrow>
+      </msubsup>
+    </math>
+
+</body></html>
diff --git a/layout/reftests/mathml/munder-mover-align-accent-false-ref.html b/layout/reftests/mathml/munder-mover-align-accent-false-ref.html
new file mode 100644
index 0000000000..ff98924f80
--- /dev/null
+++ b/layout/reftests/mathml/munder-mover-align-accent-false-ref.html
@@ -0,0 +1,114 @@
+<!DOCTYPE html>
+<html>
+  <head><title></title></head>
+  <body>
+    <h2> Test with accent="false" </h2>
+    <table border="1">
+      <tr>
+	<th colspan="2">mover</th>
+	<th colspan="2">munder</th>
+      </tr>
+      <tr>
+	<td align="center"><mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	  </mrow></td>
+      </tr>
+      <tr>
+	<td align="center">
+	  <math>
+	    <mover>
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	    </mover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <mover>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </mover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munder>
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	    </munder>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munder>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munder>
+	  </math>
+	  </td>
+      </tr>
+    </table>
+    <table>
+      <tr>
+	<th>
+	  <h5>Under & Over</h5>
+	  
+	  <math>
+	    <mrow>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </mrow>
+	  </math>
+	</th>
+	<th>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
+	<th>
+	  <h5>Base</h5>
+	  
+	  <math>
+	    <mrow>
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	    </mrow>
+	  </math>
+	</th>
+      </tr>
+    </table>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munder-mover-align-accent-false.html b/layout/reftests/mathml/munder-mover-align-accent-false.html
new file mode 100644
index 0000000000..14696c286d
--- /dev/null
+++ b/layout/reftests/mathml/munder-mover-align-accent-false.html
@@ -0,0 +1,98 @@
+<!DOCTYPE html>
+<html>
+  <head><title></title></head>
+  <body>
+    <h2> Test with accent="false" </h2>
+    <table border="1">
+      <tr>
+	<th colspan="2">mover</th>
+	<th colspan="2">munder</th>
+      </tr>
+      <tr>
+	<td align="center"><mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	  </mrow></td>
+      </tr>
+      <tr>
+	<td align="center">
+	  <math>
+	    <mover>
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </mover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <mover>
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </mover>
+	  </math>
+	  </td>
+	<td align="center">
+	  <math>
+	    <munder>
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </munder>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munder>
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munder>
+	  </math>
+	  </td>
+      </tr>
+    </table>
+    <table>
+      <tr>
+      <th>
+	<h5>Under & Over</h5>
+      
+	<math>
+	  <mrow>
+	    <mspace height="15px" width="25px" mathbackground="red"/>
+	  </mrow>
+	</math>
+      </th>
+      <th>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
+      <th>
+	<h5>Base</h5>
+	
+	<math>
+	  <mrow>
+	    <mspace height="15px" width="25px" mathbackground="blue"/>
+	  </mrow>
+	</math>
+      </th>
+      </tr>
+    </table>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munder-mover-align-accent-true-ref.html b/layout/reftests/mathml/munder-mover-align-accent-true-ref.html
new file mode 100644
index 0000000000..9ed8c4e518
--- /dev/null
+++ b/layout/reftests/mathml/munder-mover-align-accent-true-ref.html
@@ -0,0 +1,114 @@
+<!DOCTYPE html>
+<html>
+  <head><title></title></head>
+  <body>
+    <h2> Test with accent="true" </h2>
+    <table border="1">
+      <tr>
+	<th colspan="2">mover</th>
+	<th colspan="2">munder</th>
+      </tr>
+      <tr>
+	<td align="center"><mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	  </mrow></td>
+      </tr>
+      <tr>
+	<td align="center">
+	  <math>
+	    <mover accent="true">
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	    </mover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <mover accent="true">
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </mover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munder accentunder="true">
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	    </munder>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munder accentunder="true">
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munder>
+	  </math>
+	  </td>
+      </tr>
+    </table>
+    <table>
+      <tr>
+	<th>
+	  <h5>Under & Over</h5>
+	  
+	  <math>
+	    <mrow>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </mrow>
+	  </math>
+	</th>
+	<th>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
+	<th>
+	  <h5>Base</h5>
+	  
+	  <math>
+	    <mrow>
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	    </mrow>
+	  </math>
+	</th>
+      </tr>
+    </table>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munder-mover-align-accent-true.html b/layout/reftests/mathml/munder-mover-align-accent-true.html
new file mode 100644
index 0000000000..e98e0ef677
--- /dev/null
+++ b/layout/reftests/mathml/munder-mover-align-accent-true.html
@@ -0,0 +1,98 @@
+<!DOCTYPE html>
+<html>
+  <head><title></title></head>
+  <body>
+    <h2> Test with accent="true" </h2>
+    <table border="1">
+      <tr>
+	<th colspan="2">mover</th>
+	<th colspan="2">munder</th>
+      </tr>
+      <tr>
+	<td align="center"><mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow>
+	</td>
+	<td align="center">
+	  <mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	  </mrow></td>
+      </tr>
+      <tr>
+	<td align="center">
+	  <math>
+	    <mover accent="true">
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </mover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <mover accent="true">
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </mover>
+	  </math>
+	  </td>
+	<td align="center">
+	  <math>
+	    <munder accentunder="true">
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </munder>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munder accentunder="true">
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munder>
+	  </math>
+	  </td>
+      </tr>
+    </table>
+    <table>
+      <tr>
+      <th>
+	<h5>Under & Over</h5>
+      
+	<math>
+	  <mrow>
+	    <mspace height="15px" width="25px" mathbackground="red"/>
+	  </mrow>
+	</math>
+      </th>
+      <th>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
+      <th>
+	<h5>Base</h5>
+	
+	<math>
+	  <mrow>
+	    <mspace height="15px" width="25px" mathbackground="blue"/>
+	  </mrow>
+	</math>
+      </th>
+      </tr>
+    </table>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munderover-align-accent-false-ref.html b/layout/reftests/mathml/munderover-align-accent-false-ref.html
new file mode 100644
index 0000000000..7948407abf
--- /dev/null
+++ b/layout/reftests/mathml/munderover-align-accent-false-ref.html
@@ -0,0 +1,132 @@
+<!DOCTYPE html>
+<html>
+  <head><title></title></head>
+  <body>
+    <h2> Test with accent="false" </h2>
+    <table border="1">
+      <tr>
+	<th colspan="6">munderover</th>
+      </tr>
+      <tr>
+	<td align="center"><math><mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	    <mo>&lt;</mo>
+	    <mi>Under<mi>
+	  </mrow></math>
+	</td>
+	<td align="center">
+	  <math><mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	    <mo>&gt;</mo>
+	    <mi>Under</mi>
+	  </mrow></math>
+	</td>
+	<td align="center">
+	  <math><mrow>
+	    <mi>Over = Under</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow></math>
+	</td>
+	<td align="center"><math><mrow>
+	    <mi>Over = Under</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	</mrow></math></td>
+      </tr>
+      <tr>
+	<td align="center">
+	  <math>
+	    <munderover accent="false" accentunder="false">
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="50px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover accent="false" accentunder="false">
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="50px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover accent="false" accentunder="false">
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover accent="false" accentunder="false">
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	  </td>
+      </tr>
+    </table>
+    <table>
+      <tr>
+	<th>
+	  <h5>Under & Over</h5>
+	  
+	  <math>
+	    <mrow>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </mrow>
+	  </math>
+	</th>
+	<th>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
+	<th>
+	  <h5>Base</h5>
+	  
+	  <math>
+	    <mrow>
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	    </mrow>
+	  </math>
+	</th>
+      </tr>
+    </table>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munderover-align-accent-false.html b/layout/reftests/mathml/munderover-align-accent-false.html
new file mode 100644
index 0000000000..d2ab965d96
--- /dev/null
+++ b/layout/reftests/mathml/munderover-align-accent-false.html
@@ -0,0 +1,104 @@
+<!DOCTYPE html>
+<html>
+  <head><title></title></head>
+  <body>
+    <h2> Test with accent="false" </h2>
+    <table border="1">
+      <tr>
+	<th colspan="4">munderover</th>
+      </tr>
+      <tr>
+	<td align="center"><math><mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	    <mo>&lt;</mo>
+	    <mi>Under<mi>
+	  </mrow></math>
+	</td>
+	<td align="center">
+	  <math><mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	    <mo>&gt;</mo>
+	    <mi>Under</mi>
+	  </mrow></math>
+	</td>
+	<td align="center">
+	  <math><mrow>
+	    <mi>Over = Under</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow></math>
+	</td>
+	<td align="center"><math><mrow>
+	    <mi>Over = Under</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	</mrow></math></td>
+      </tr>
+      <tr>
+	<td align="center">
+	  <math>
+	    <munderover>
+	      <mspace height="15px" width="50px" mathbackground="blue"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover>
+	      <mspace height="15px" width="50px" mathbackground="blue"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	  </td>
+	<td align="center">
+	  <math>
+	    <munderover>
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover>
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	</td>
+      </tr>
+    </table>
+    <table>
+      <tr>
+      <th>
+	<h5>Under & Over</h5>
+      
+	<math>
+	  <mrow>
+	    <mspace height="15px" width="25px" mathbackground="red"/>
+	  </mrow>
+	</math>
+      </th>
+      <th>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
+      <th>
+	<h5>Base</h5>
+	
+	<math>
+	  <mrow>
+	    <mspace height="15px" width="25px" mathbackground="blue"/>
+	  </mrow>
+	</math>
+      </th>
+      </tr>
+    </table>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munderover-align-accent-true-ref.html b/layout/reftests/mathml/munderover-align-accent-true-ref.html
new file mode 100644
index 0000000000..d4c88c06e1
--- /dev/null
+++ b/layout/reftests/mathml/munderover-align-accent-true-ref.html
@@ -0,0 +1,132 @@
+<!DOCTYPE html>
+<html>
+  <head><title></title></head>
+  <body>
+    <h2> Test with accent="true" </h2>
+    <table border="1">
+      <tr>
+	<th colspan="6">munderover</th>
+      </tr>
+      <tr>
+	<td align="center"><math><mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	    <mo>&lt;</mo>
+	    <mi>Under<mi>
+	  </mrow></math>
+	</td>
+	<td align="center">
+	  <math><mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	    <mo>&gt;</mo>
+	    <mi>Under</mi>
+	  </mrow></math>
+	</td>
+	<td align="center">
+	  <math><mrow>
+	    <mi>Over = Under</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow></math>
+	</td>
+	<td align="center"><math><mrow>
+	    <mi>Over = Under</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	</mrow></math></td>
+      </tr>
+      <tr>
+	<td align="center">
+	  <math>
+	    <munderover accent="true" accentunder="true">
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="50px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover accent="true" accentunder="true">
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="50px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover accent="true" accentunder="true">
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="red"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover accent="true" accentunder="true">
+	      <mrow>
+		<mspace height="15px" width="25px"/>
+		<mspace height="15px" width="25px" mathbackground="blue"/>
+		<mspace height="15px" width="25px"/>
+	      </mrow>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	  </td>
+      </tr>
+    </table>
+    <table>
+      <tr>
+	<th>
+	  <h5>Under & Over</h5>
+	  
+	  <math>
+	    <mrow>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </mrow>
+	  </math>
+	</th>
+	<th>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
+	<th>
+	  <h5>Base</h5>
+	  
+	  <math>
+	    <mrow>
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	    </mrow>
+	  </math>
+	</th>
+      </tr>
+    </table>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munderover-align-accent-true.html b/layout/reftests/mathml/munderover-align-accent-true.html
new file mode 100644
index 0000000000..3067ae5ea8
--- /dev/null
+++ b/layout/reftests/mathml/munderover-align-accent-true.html
@@ -0,0 +1,104 @@
+<!DOCTYPE html>
+<html>
+  <head><title></title></head>
+  <body>
+    <h2> Test with accent="true" </h2>
+    <table border="1">
+      <tr>
+	<th colspan="4">munderover</th>
+      </tr>
+      <tr>
+	<td align="center"><math><mrow>
+	    <mi>Over</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	    <mo>&lt;</mo>
+	    <mi>Under<mi>
+	  </mrow></math>
+	</td>
+	<td align="center">
+	  <math><mrow>
+	    <mi>Over</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	    <mo>&gt;</mo>
+	    <mi>Under</mi>
+	  </mrow></math>
+	</td>
+	<td align="center">
+	  <math><mrow>
+	    <mi>Over = Under</mi>
+	    <mo>&lt;</mo>
+	    <mi>Base</mi>
+	  </mrow></math>
+	</td>
+	<td align="center"><math><mrow>
+	    <mi>Over = Under</mi>
+	    <mo>&gt;</mo>
+	    <mi>Base</mi>
+	</mrow></math></td>
+      </tr>
+      <tr>
+	<td align="center">
+	  <math>
+	    <munderover accent="true" accentunder="true">
+	      <mspace height="15px" width="50px" mathbackground="blue"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover accent="true" accentunder="true">
+	      <mspace height="15px" width="50px" mathbackground="blue"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	  </td>
+	<td align="center">
+	  <math>
+	    <munderover accent="true" accentunder="true">
+	      <mspace height="15px" width="75px" mathbackground="blue"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	      <mspace height="15px" width="25px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	</td>
+	<td align="center">
+	  <math>
+	    <munderover accent="true" accentunder="true">
+	      <mspace height="15px" width="25px" mathbackground="blue"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	      <mspace height="15px" width="75px" mathbackground="red"/>
+	    </munderover>
+	  </math>
+	</td>
+      </tr>
+    </table>
+    <table>
+      <tr>
+      <th>
+	<h5>Under & Over</h5>
+      
+	<math>
+	  <mrow>
+	    <mspace height="15px" width="25px" mathbackground="red"/>
+	  </mrow>
+	</math>
+      </th>
+      <th>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
+      <th>
+	<h5>Base</h5>
+	
+	<math>
+	  <mrow>
+	    <mspace height="15px" width="25px" mathbackground="blue"/>
+	  </mrow>
+	</math>
+      </th>
+      </tr>
+    </table>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munderover-empty-scripts-ref.html b/layout/reftests/mathml/munderover-empty-scripts-ref.html
new file mode 100644
index 0000000000..27d858309d
--- /dev/null
+++ b/layout/reftests/mathml/munderover-empty-scripts-ref.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Test munderover with empty scripts</title>
+  </head>
+  <body>
+
+    <p>munder / munderover with empty overscript:
+    <math>
+      <munderover style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+        <mspace></mspace>
+      </munderover>
+    </math></p>
+
+    <p>mover / munderover with empty underscript:
+    <math>
+      <munderover style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mspace></mspace>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+      </munderover>
+    </math></p>
+
+    <p>mrow / munder with empty scripts:
+    <math>
+      <munderover style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mspace></mspace>
+        <mspace></mspace>
+      </munderover>
+    </math></p>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/munderover-empty-scripts.html b/layout/reftests/mathml/munderover-empty-scripts.html
new file mode 100644
index 0000000000..5704c5c74d
--- /dev/null
+++ b/layout/reftests/mathml/munderover-empty-scripts.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Test munderover with empty scripts</title>
+  </head>
+  <body>
+
+    <p>munder / munderover with empty overscript:
+    <math>
+      <munder style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+      </munder>
+    </math></p>
+
+    <p>mover / munderover with empty underscript:
+    <math>
+      <mover style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+        <mtext style="background-color: rgba(0, 255, 0, 0.4);">bbb</mtext>
+      </mover>
+    </math></p>
+
+    <p>mrow / munder with empty scripts:
+    <math>
+      <mrow style="background: red;">
+        <mtext style="background-color: rgba(0, 0, 255, 0.4);">AAA</mtext>
+      </mrow>
+    </math></p>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/overbar-width-1-ref.xhtml b/layout/reftests/mathml/overbar-width-1-ref.xhtml
new file mode 100644
index 0000000000..64e89f403f
--- /dev/null
+++ b/layout/reftests/mathml/overbar-width-1-ref.xhtml
@@ -0,0 +1,26 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <style type="text/css">
+      html { background-color: grey; }
+      div { display: inline-block;
+            font-size: 30px;
+            line-height: 60px; /* Ensure space for overbar */
+            border: 1px solid white;
+            padding: 2px; /* 10% error allowed in char selection */
+            background-color: black;
+            color: red; }
+    </style>
+  </head>
+<body>
+  <div>
+    <math xmlns="http://www.w3.org/1998/Math/MathML">
+      <mphantom>
+	<mover>
+	  <mi>ai</mi>
+	  <mo>&#xaf;</mo>
+	</mover>
+      </mphantom>
+    </math>
+  </div>
+</body>
+</html>
diff --git a/layout/reftests/mathml/overbar-width-1.xhtml b/layout/reftests/mathml/overbar-width-1.xhtml
new file mode 100644
index 0000000000..ab261d061d
--- /dev/null
+++ b/layout/reftests/mathml/overbar-width-1.xhtml
@@ -0,0 +1,25 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Check width of stretchy OverBar</title>
+    <style type="text/css">
+      html { background-color: grey; }
+      div { display: inline-block;
+            font-size: 30px;
+            line-height: 60px; /* Ensure space for overbar */
+            border: 1px solid white;
+            padding: 2px; /* 10% error allowed in char selection */
+            background-color: black;
+            color: black; }
+    </style>
+  </head>
+<body>
+  <div>
+    <math xmlns="http://www.w3.org/1998/Math/MathML">
+      <mover>
+	<mi>ai</mi>
+	<mo>&#xaf;</mo>
+      </mover>
+    </math>
+  </div>
+</body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-1.html b/layout/reftests/mathml/radicalbar-1.html
new file mode 100644
index 0000000000..326164c0fa
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-1.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+  <html>
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="visible">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-1a.html b/layout/reftests/mathml/radicalbar-1a.html
new file mode 100644
index 0000000000..bf2e5147ae
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-1a.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+  <html reftest-zoom=".5">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="visible">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-1b.html b/layout/reftests/mathml/radicalbar-1b.html
new file mode 100644
index 0000000000..a469943e79
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-1b.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+  <html reftest-zoom=".4">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="visible">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-1c.html b/layout/reftests/mathml/radicalbar-1c.html
new file mode 100644
index 0000000000..0485fe4136
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-1c.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+  <html reftest-zoom=".3">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="visible">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-1d.html b/layout/reftests/mathml/radicalbar-1d.html
new file mode 100644
index 0000000000..f89db4ded3
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-1d.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+  <html reftest-zoom=".2">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="visible">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-2.html b/layout/reftests/mathml/radicalbar-2.html
new file mode 100644
index 0000000000..1870493cb4
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-2.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html>
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="visible">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-2a.html b/layout/reftests/mathml/radicalbar-2a.html
new file mode 100644
index 0000000000..9856fa868c
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-2a.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html reftest-zoom="0.5">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="visible">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-2b.html b/layout/reftests/mathml/radicalbar-2b.html
new file mode 100644
index 0000000000..7df074c40e
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-2b.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html reftest-zoom="0.4">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="visible">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-2c.html b/layout/reftests/mathml/radicalbar-2c.html
new file mode 100644
index 0000000000..138bad31ab
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-2c.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html reftest-zoom="0.3">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="visible">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-2d.html b/layout/reftests/mathml/radicalbar-2d.html
new file mode 100644
index 0000000000..7f12882422
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-2d.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html reftest-zoom="0.2">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="hidden">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="visible">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-3.html b/layout/reftests/mathml/radicalbar-3.html
new file mode 100644
index 0000000000..12fa3ae050
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-3.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html>
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="visible">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-3a.html b/layout/reftests/mathml/radicalbar-3a.html
new file mode 100644
index 0000000000..24ebfec8e5
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-3a.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html reftest-zoom="0.5">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="visible">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-3b.html b/layout/reftests/mathml/radicalbar-3b.html
new file mode 100644
index 0000000000..1aeafb6cb7
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-3b.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html reftest-zoom="0.4">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="visible">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-3c.html b/layout/reftests/mathml/radicalbar-3c.html
new file mode 100644
index 0000000000..e9e7e7ae55
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-3c.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html reftest-zoom="0.3">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="visible">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/radicalbar-3d.html b/layout/reftests/mathml/radicalbar-3d.html
new file mode 100644
index 0000000000..7d780af44c
--- /dev/null
+++ b/layout/reftests/mathml/radicalbar-3d.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+  <html reftest-zoom="0.2">
+  <head>
+    <!-- Default to invisible text -->
+    <style type="text/css" media="screen, print">
+      .hidden {
+        color: white;
+      }
+      .visible {
+        color: black;
+      }
+    </style>
+  </head>
+  <body>
+    <!-- Nest successive radicals and test that the horizontal bar of one of them is drawn.
+         Because the comparison is for inequality with about:blank, at most one can be visible -->
+    <math>
+      <mrow>
+        <msqrt class="hidden">
+          <mspace width="1em" height="1em" />
+          <msqrt class="hidden">
+            <mspace width="1em" height="1em" />
+            <msqrt class="hidden">
+              <mspace width="1em" height="1em" />
+              <msqrt class="hidden">
+                <mspace width="1em" height="1em" />
+                <msqrt class="visible">
+                  <mspace width="1em" height="1em" />
+                  <msqrt class="hidden">
+                    <mspace width="1em" height="1em" />
+                    <msqrt class="hidden">
+                      <mspace width="20em" height="1em" />
+                    </msqrt>
+                  </msqrt>
+                </msqrt>
+              </msqrt>
+            </msqrt>
+          </msqrt>
+        </msqrt>
+      </mrow>
+    </math>
+
+    <!-- Block out all but the horizontal bar of the visible radical -->
+    <div style="position: absolute; top: 5px; left: 0px;
+                width: 20em; height: 10em; background: white;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/reftest.list b/layout/reftests/mathml/reftest.list
new file mode 100644
index 0000000000..b143a25174
--- /dev/null
+++ b/layout/reftests/mathml/reftest.list
@@ -0,0 +1,55 @@
+random-if(smallScreen&&Android) fuzzy(0-255,0-200) fuzzy-if(geckoview,201-216,200-250) fuzzy-if(winWidget,114-255,245-361) fuzzy-if(OSX,79-153,240-250) == mirror-op-1.html mirror-op-1-ref.html
+!= mirror-op-2.html mirror-op-2-ref.html
+!= mirror-op-3.html mirror-op-3-ref.html
+!= mirror-op-4.html mirror-op-4-ref.html
+== overbar-width-1.xhtml overbar-width-1-ref.xhtml
+== stretchy-largeop-1.html stretchy-largeop-1-ref.html
+== stretchy-largeop-2.html stretchy-largeop-2-ref.html
+== stretchy-largeop-3.html stretchy-largeop-3-ref.html
+== underbar-width-1.xhtml underbar-width-1-ref.xhtml
+== semantics-1.xhtml semantics-1-ref.xhtml
+== semantics-2.html semantics-2-ref.html
+== semantics-3.html semantics-3-ref.html
+pref(mathml.stixgeneral_operator_stretching.disabled,false) == semantics-5.html semantics-5-ref.html # bug 1309429; bug 1648335
+fuzzy-if(OSX,0-16,0-8) == mstyle-3.xhtml mstyle-3-ref.xhtml
+fuzzy-if(OSX,0-1,0-4) == mstyle-4.xhtml mstyle-4-ref.xhtml
+== scale-stretchy-1.xhtml scale-stretchy-1-ref.xhtml
+!= scale-stretchy-2.xhtml scale-stretchy-2-ref.xhtml
+fails-if(OSX>=1010) == scale-stretchy-3.xhtml scale-stretchy-3-ref.xhtml
+!= scale-stretchy-4.xhtml scale-stretchy-4-ref.xhtml
+!= scale-stretchy-5.xhtml scale-stretchy-5-ref.xhtml
+!= stretchy-1.html stretchy-1-ref.html
+== mpadded-7.html mpadded-7-ref.html
+== mpadded-8.html mpadded-8-ref.html
+== mpadded-9.html mpadded-9-ref.html
+== scriptlevel-movablelimits-1.html scriptlevel-movablelimits-1-ref.html
+== munderover-align-accent-false.html munderover-align-accent-false-ref.html
+== munderover-align-accent-true.html munderover-align-accent-true-ref.html
+== munder-mover-align-accent-true.html munder-mover-align-accent-true-ref.html
+== munder-mover-align-accent-false.html munder-mover-align-accent-false-ref.html
+== munderover-empty-scripts.html munderover-empty-scripts-ref.html
+== mo-glyph-size.html mo-glyph-size-ref.html
+fuzzy(0-1,0-80) fuzzy-if(Android,0-255,0-105) fuzzy-if(gtkWidget,0-255,0-136) skip-if(winWidget) == multiscripts-1.html multiscripts-1-ref.html # Windows: bug 1314684; Android: bug 1392254; Linux: bug 1599638
+== mathml-mmultiscript-base.html mathml-mmultiscript-base-ref.html
+== mathml-mmultiscript-mprescript.html mathml-mmultiscript-mprescript-ref.html
+== mmultiscript-align.html mmultiscript-align-ref.html
+fails-if(winWidget) fuzzy-if(gtkWidget,255-255,776226-776226) == subscript-italic-correction.html subscript-italic-correction-ref.html # bug 961482 (Windows), bug 1599640 (Linux)
+
+# radicalbar*.html tests rely on reftest-zoom to verify the visibility of the
+# radical bar at different zoom levels. There does not seem to be any equivalent
+# way of testing that via WPT. See bug 1850661.
+!= radicalbar-1.html about:blank
+!= radicalbar-1a.html about:blank
+!= radicalbar-1b.html about:blank
+!= radicalbar-1c.html about:blank
+!= radicalbar-1d.html about:blank
+!= radicalbar-2.html about:blank
+!= radicalbar-2a.html about:blank
+!= radicalbar-2b.html about:blank
+!= radicalbar-2c.html about:blank
+!= radicalbar-2d.html about:blank
+!= radicalbar-3.html about:blank
+!= radicalbar-3a.html about:blank
+!= radicalbar-3b.html about:blank
+!= radicalbar-3c.html about:blank
+!= radicalbar-3d.html about:blank
diff --git a/layout/reftests/mathml/scale-stretchy-1-ref.xhtml b/layout/reftests/mathml/scale-stretchy-1-ref.xhtml
new file mode 100644
index 0000000000..e1182941c0
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-1-ref.xhtml
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Maximal size for a vertical arrow stretched by scaling</title>
+  </head>
+
+  <body>
+
+    <table style="position: absolute;">
+      <tr>
+        <td><div style="height: 200px; width: 5px; background: black"/></td>
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <mrow>
+              <mspace height="50px" depth="50px" width="5px"
+                      style="background: yellow" />
+              <mspace height="55px" depth="55px" width="50px"
+                      style="background: red;"/>
+            </mrow>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-1.xhtml b/layout/reftests/mathml/scale-stretchy-1.xhtml
new file mode 100644
index 0000000000..76f0620dfd
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-1.xhtml
@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Maximal size for a vertical arrow stretched by scaling</title>
+  </head>
+
+  <body>
+
+    <table style="position: absolute;">
+      <tr>
+        <td><div style="height: 200px; width: 5px; background: black"/></td>
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <mrow>
+              <mspace height="50px" depth="50px" width="5px"
+                      style="background: yellow" />
+              <mo style="color: blue;">&#x290B;</mo>
+            </mrow>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+    <table style="position: absolute;">
+      <tr>
+        <td><div style="height: 200px; width: 5px; background: black"/></td>
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <mrow>
+              <mspace height="50px" depth="50px" width="5px"
+                      style="background: yellow" />
+              <mspace height="55px" depth="55px" width="50px"
+                      style="background: red;"/>
+            </mrow>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-2-ref.xhtml b/layout/reftests/mathml/scale-stretchy-2-ref.xhtml
new file mode 100644
index 0000000000..e219fe0be6
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-2-ref.xhtml
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Minimal size for a vertical arrow stretched by scaling</title>
+  </head>
+
+  <body>
+
+    <table style="position: absolute;">
+      <tr>
+        <td><div style="height: 200px; width: 5px; background: black"/></td>
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <mrow>
+              <mspace height="50px" depth="50px" width="5px"
+                      style="background: yellow" />
+              <mspace height="44px" depth="44px" width="50px"
+                      style="background: green;"/>
+            </mrow>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-2.xhtml b/layout/reftests/mathml/scale-stretchy-2.xhtml
new file mode 100644
index 0000000000..e89910586d
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-2.xhtml
@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Minimal size for a vertical arrow stretched by scaling</title>
+  </head>
+
+  <body>
+
+    <table style="position: absolute;">
+      <tr>
+        <td><div style="height: 200px; width: 5px; background: black"/></td>
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <mrow>
+              <mspace height="50px" depth="50px" width="5px"
+                      style="background: yellow" />
+              <mo style="color: blue;">&#x290B;</mo>
+            </mrow>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+    <table style="position: absolute;">
+      <tr>
+        <td><div style="height: 200px; width: 5px; background: black"/></td>
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <mrow>
+              <mspace height="50px" depth="50px" width="5px"
+                      style="background: yellow" />
+              <mspace height="44px" depth="44px" width="50px"
+                      style="background: green;"/>
+            </mrow>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-3-ref.xhtml b/layout/reftests/mathml/scale-stretchy-3-ref.xhtml
new file mode 100644
index 0000000000..7a671c1cad
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-3-ref.xhtml
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Maximal size for a horizontal arrow stretched by scaling</title>
+  </head>
+
+  <body>
+
+    <table style="position: absolute;">
+      <tr align="center">
+        <td><div style="width: 200px; height: 5px; background: black"/></td>
+      </tr>
+      <tr align="center">
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <munder accentunder="false">
+              <mspace width="100px" height="5px" style="background: yellow"/>
+              <mspace width="110px" height="25px" depth="25px"
+                      style="background: red;"/>
+            </munder>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-3.xhtml b/layout/reftests/mathml/scale-stretchy-3.xhtml
new file mode 100644
index 0000000000..a21b03f61d
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-3.xhtml
@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Maximal size for a horizontal arrow stretched by scaling</title>
+  </head>
+
+  <body>
+
+    <table style="position: absolute;">
+      <tr align="center">
+        <td><div style="width: 200px; height: 5px; background: black"/></td>
+      </tr>
+      <tr align="center">
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <munder accentunder="false">
+              <mspace width="100px" height="5px" style="background: yellow"/>
+              <mo style="color: blue;">&#x21DB;</mo>
+            </munder>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+    <table style="position: absolute;">
+      <tr align="center">
+        <td><div style="width: 200px; height: 5px; background: black"/></td>
+      </tr>
+      <tr align="center">
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <munder accentunder="false">
+              <mspace width="100px" height="5px" style="background: yellow"/>
+              <mspace width="110px" height="25px" depth="25px"
+                      style="background: red;"/>
+            </munder>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-4-ref.xhtml b/layout/reftests/mathml/scale-stretchy-4-ref.xhtml
new file mode 100644
index 0000000000..87cb94d305
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-4-ref.xhtml
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Minimal size for a horizontal arrow stretched by scaling</title>
+  </head>
+
+  <body>
+
+    <table style="position: absolute;">
+      <tr align="center">
+        <td><div style="width: 200px; height: 5px; background: black"/></td>
+      </tr>
+      <tr align="center">
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <munder>
+              <mspace width="100px" height="5px" style="background: yellow"/>
+              <mspace width="88px" height="25px" depth="25px"
+                      style="background: green;"/>
+            </munder>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-4.xhtml b/layout/reftests/mathml/scale-stretchy-4.xhtml
new file mode 100644
index 0000000000..693fdc7ed4
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-4.xhtml
@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Minimal size for a horizontal arrow stretched by scaling</title>
+  </head>
+
+  <body>
+
+    <table style="position: absolute;">
+      <tr align="center">
+        <td><div style="width: 200px; height: 5px; background: black"/></td>
+      </tr>
+      <tr align="center">
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <munder>
+              <mspace width="100px" height="5px" style="background: yellow"/>
+              <mo style="color: blue;">&#x21DB;</mo>
+            </munder>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+    <table style="position: absolute;">
+      <tr align="center">
+        <td><div style="width: 200px; height: 5px; background: black"/></td>
+      </tr>
+      <tr align="center">
+        <td>
+          <math xmlns="http://www.w3.org/1998/Math/MathML">
+            <munder>
+              <mspace width="100px" height="5px" style="background: yellow"/>
+              <mspace width="88px" height="25px" depth="25px"
+                      style="background: green;"/>
+            </munder>
+          </math>
+        </td>
+      </tr>
+    </table>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-5-ref.xhtml b/layout/reftests/mathml/scale-stretchy-5-ref.xhtml
new file mode 100644
index 0000000000..8dc382e304
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-5-ref.xhtml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <title>Largeop in display mode stretched by scaling</title>
+</head>
+
+<body>
+
+<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+  <mo largeop="false">&#x2A0C;</mo>
+</math>
+
+</body>
+</html>
diff --git a/layout/reftests/mathml/scale-stretchy-5.xhtml b/layout/reftests/mathml/scale-stretchy-5.xhtml
new file mode 100644
index 0000000000..a79e757d73
--- /dev/null
+++ b/layout/reftests/mathml/scale-stretchy-5.xhtml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <title>Largeop in display mode stretched by scaling</title>
+</head>
+
+<body>
+
+<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+  <mo>&#x2A0C;</mo>
+</math>
+
+</body>
+</html>
diff --git a/layout/reftests/mathml/scriptlevel-movablelimits-1-ref.html b/layout/reftests/mathml/scriptlevel-movablelimits-1-ref.html
new file mode 100644
index 0000000000..bbffa910ab
--- /dev/null
+++ b/layout/reftests/mathml/scriptlevel-movablelimits-1-ref.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test accent/accentunder</title></head>
+  <body>    
+    <math displaystyle="false">
+      <munderover>
+	<mo>&#x2211;</mo>
+	<mi>a</mi>
+	<mi>b</mi>
+      </munderover>
+    </math>
+    <math displaystyle="false">
+      <munder>
+	<mo>&#x2211;</mo>
+	<mi>a</mi>
+      </munder>
+    </math>
+    <math displaystyle="false">
+      <mover>
+	<mo>&#x2211;</mo>
+	<mi>a</mi>
+      </mover>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/scriptlevel-movablelimits-1.html b/layout/reftests/mathml/scriptlevel-movablelimits-1.html
new file mode 100644
index 0000000000..f3ef2e53ba
--- /dev/null
+++ b/layout/reftests/mathml/scriptlevel-movablelimits-1.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test accent/accentunder</title></head>
+  <body>
+    <math displaystyle="false">
+      <munderover accentunder="true" accent="true">
+	<mo>&#x2211;</mo>
+	<mi>a</mi>
+	<mi>b</mi>
+      </munderover>
+    </math>
+    <math displaystyle="false">
+      <munder accentunder="true">
+	<mo>&#x2211;</mo>
+	<mi>a</mi>
+      </munder>
+    </math>
+    <math displaystyle="false">
+      <mover accent="true">
+	<mo>&#x2211;</mo>
+	<mi>a</mi>
+      </mover>
+    </math>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/semantics-1-ref.xhtml b/layout/reftests/mathml/semantics-1-ref.xhtml
new file mode 100644
index 0000000000..f5a6d4d493
--- /dev/null
+++ b/layout/reftests/mathml/semantics-1-ref.xhtml
@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta http-equiv="content-type"
+  content="application/xhtml+xml; charset=utf-8" />
+  <title>Various tests for semantics</title>
+  <style>
+    @font-face
+    {
+        font-family: Ahem;
+        src: url(../fonts/Ahem.ttf);
+    }
+    math, p {
+        font: 25px Ahem;
+    }
+  </style>
+</head>
+
+<body>
+<!-- displaystyle (bug 468059) -->
+<p><math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+  <semantics>
+    <mstyle displaystyle="true">
+      <munderover>
+        <mo movablelimits="true">pXp</mo>
+        <mtext>XpXpXp</mtext>
+        <mtext>XpXpXp</mtext>
+      </munderover>
+    </mstyle>
+  </semantics>
+</math></p>
+
+<!-- unwanted whitespace (bug 512418) -->
+<p>XpXpXp<math xmlns="http://www.w3.org/1998/Math/MathML">
+    <mrow>
+      <mrow>
+        <mo>lcm</mo>
+        <mo>(</mo>
+        <mn>a</mn>
+        <mo>,</mo>
+        <mn>b</mn>
+        <mo>)</mo>
+      </mrow>
+      <mo>=</mo>
+      <mfrac>
+        <mrow>
+          <mo>(</mo>
+          <mn>a</mn>
+          <mo>&#x2062;</mo>
+          <mn>b</mn>
+          <mo>)</mo>
+        </mrow>
+        <mrow>
+          <mo>gcd</mo>
+          <mo>(</mo>
+          <mn>a</mn>
+          <mo>,</mo>
+          <mn>b</mn>
+          <mo>)</mo>
+        </mrow>
+      </mfrac>
+    </mrow>
+</math>XpXpXp</p>
+
+</body>
+</html>
diff --git a/layout/reftests/mathml/semantics-1.xhtml b/layout/reftests/mathml/semantics-1.xhtml
new file mode 100644
index 0000000000..d4ea92a4e5
--- /dev/null
+++ b/layout/reftests/mathml/semantics-1.xhtml
@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="utf-8"?>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta http-equiv="content-type"
+  content="application/xhtml+xml; charset=utf-8" />
+  <title>Various tests for semantics</title>
+  <style>
+    @font-face
+    {
+        font-family: Ahem;
+        src: url(../fonts/Ahem.ttf);
+    }
+    math, p {
+        font: 25px Ahem;
+    }
+</style>
+</head>
+
+<body>
+<!-- displaystyle (bug 468059) -->
+<p><math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+    <semantics>
+      <munderover>
+        <mo movablelimits="true">pXp</mo>
+        <mtext>XpXpXp</mtext>
+        <mtext>XpXpXp</mtext>
+      </munderover>
+    </semantics>
+</math></p>
+
+<!-- unwanted whitespace (bug 512418) -->
+<p>XpXpXp<math xmlns="http://www.w3.org/1998/Math/MathML">
+  <semantics>
+    <mrow>
+      <mrow>
+        <mo>lcm</mo>
+        <mo>(</mo>
+        <mn>a</mn>
+        <mo>,</mo>
+        <mn>b</mn>
+        <mo>)</mo>
+      </mrow>
+      <mo>=</mo>
+      <mfrac>
+        <mrow>
+          <mo>(</mo>
+          <mn>a</mn>
+          <mo>&#x2062;</mo>
+          <mn>b</mn>
+          <mo>)</mo>
+        </mrow>
+        <mrow>
+          <mo>gcd</mo>
+          <mo>(</mo>
+          <mn>a</mn>
+          <mo>,</mo>
+          <mn>b</mn>
+          <mo>)</mo>
+        </mrow>
+      </mfrac>
+    </mrow>
+  </semantics>
+</math>XpXpXp</p>
+
+</body>
+</html>
diff --git a/layout/reftests/mathml/semantics-2-ref.html b/layout/reftests/mathml/semantics-2-ref.html
new file mode 100644
index 0000000000..43b52b17db
--- /dev/null
+++ b/layout/reftests/mathml/semantics-2-ref.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Various tests for semantics</title>
+  <meta charset="utf-8"/>
+</head>
+
+<body>
+  <p>Empty semantics: <math><mrow></mrow></math></p>
+  <p>annotation: <math><mrow><annotation>annotation</annotation></mrow></math></p>
+  <p>annotation-xml: <math><mrow><annotation-xml encoding="MathML-Presentation"><mtext>annotation-xml</mtext></annotation-xml></mrow></math></p>
+  <p>presentation MathML (no annotations): <math><mrow><mtext>presentation MathML</mtext></mrow></math></p>
+  <p>content MathML (no annotations): <math><mrow><csymbol>content MathML</csymbol></mrow></math></p>
+  <p>presentation MathML ; annotation: <math><mrow><mtext>presentation MathML</mtext></mrow></math></p>
+  <p>presentation MathML ; annotation-xml: <math><mrow><mtext>presentation MathML</mtext></mrow></math></p>
+  <p>content MathML ; annotation: <math><mrow><csymbol>content MathML</csymbol></mrow></math></p>
+  <p>content MathML ; annotation-xml: <math><mrow><csymbol>content MathML</csymbol></mrow></math></p>
+</body>
+</html>
diff --git a/layout/reftests/mathml/semantics-2.html b/layout/reftests/mathml/semantics-2.html
new file mode 100644
index 0000000000..2c7d99ac3d
--- /dev/null
+++ b/layout/reftests/mathml/semantics-2.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Various tests for semantics</title>
+  <meta charset="utf-8"/>
+</head>
+
+<body>
+  <p>Empty semantics: <math><semantics></semantics></math></p>
+  <p>annotation: <math><semantics><annotation>annotation</annotation></semantics></math></p>
+  <p>annotation-xml: <math><semantics><annotation-xml encoding="MathML-Presentation"><mtext>annotation-xml</mtext></annotation-xml></semantics></math></p>
+  <p>presentation MathML (no annotations): <math><semantics><mtext>presentation MathML</mtext></semantics></math></p>
+  <p>content MathML (no annotations): <math><semantics><csymbol>content MathML</csymbol></semantics></math></p>
+  <p>presentation MathML ; annotation: <math><semantics><mtext>presentation MathML</mtext><annotation>annotation</annotation></semantics></math></p>
+  <p>presentation MathML ; annotation-xml: <math><semantics><mtext>presentation MathML</mtext><annotation-xml encoding="application/mathml-presentation+xml"><mtext>annotation-xml</mtext></annotation-xml></semantics></math></p>
+  <p>content MathML ; annotation: <math><semantics><csymbol>content MathML</csymbol><annotation>annotation</annotation></semantics></math></p>
+  <p>content MathML ; annotation-xml: <math><semantics><csymbol>content MathML</csymbol><annotation-xml encoding="application/mathml-presentation+xml"><mtext>annotation-xml</mtext></annotation-xml></semantics></math></p>
+</body>
+</html>
diff --git a/layout/reftests/mathml/semantics-3-ref.html b/layout/reftests/mathml/semantics-3-ref.html
new file mode 100644
index 0000000000..8d42de963c
--- /dev/null
+++ b/layout/reftests/mathml/semantics-3-ref.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Various tests for semantics</title>
+   <meta charset="utf-8"/>
+</head>
+
+<body>
+  <p>annotation 1: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+  <p>annotation 2: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+  <p>annotation 3: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+
+  <p>annotation-xml 1: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+  <p>annotation-xml 2: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+  <p>annotation-xml 3: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+  <p>annotation-xml 4: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+  <p>annotation-xml 5: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+  <p>annotation-xml 6: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+  <p>annotation-xml 7: <math><mrow><csymbol>Content MathML</csymbol></mrow></math></p>
+</body>
+</html>
diff --git a/layout/reftests/mathml/semantics-3.html b/layout/reftests/mathml/semantics-3.html
new file mode 100644
index 0000000000..92a93c774f
--- /dev/null
+++ b/layout/reftests/mathml/semantics-3.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Various tests for semantics</title>
+   <meta charset="utf-8"/>
+</head>
+
+<body>
+  <p>annotation 1: <math><semantics><csymbol>Content MathML</csymbol><annotation>annotation</annotation><annotation>error</annotation><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml></semantics></math></p>
+  <p>annotation 2: <math><semantics><csymbol>Content MathML</csymbol><annotation encoding="application/x-tex">\sin x + 5</annotation><annotation>error</annotation><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml></semantics></math></p>
+  <p>annotation 3: <math><semantics><csymbol>Content MathML</csymbol><annotation src="external-resource">error</annotation><annotation>annotation</annotation><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml></semantics></math></p>
+
+  <p>annotation-xml 1: <math><semantics><csymbol>Content MathML</csymbol><annotation-xml encoding="application/mathml-presentation+xml"><mtext>application/mathml-presentation+xml</mtext></annotation-xml><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml><annotation>error</annotation></semantics></math></p>
+  <p>annotation-xml 2: <math><semantics><csymbol>Content MathML</csymbol><annotation-xml encoding="MathML-Presentation"><mtext>MathML-Presentation</mtext></annotation-xml><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml><annotation>error</annotation></semantics></math></p>
+  <p>annotation-xml 3: <math><semantics><csymbol>Content MathML</csymbol><annotation-xml encoding="image/svg+xml"><svg xmlns="http://www.w3.org/2000/svg" height="2em"><text y="1em">image/svg+xml</text></svg></annotation-xml><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml><annotation>error</annotation></semantics></math></p>
+  <p>annotation-xml 4: <math><semantics><csymbol>Content MathML</csymbol><annotation-xml encoding="SVG1.1"><svg xmlns="http://www.w3.org/2000/svg" height="2em"><text y="1em">SVG1.1</text></svg></annotation-xml><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml><annotation>error</annotation></semantics></math></p>
+  <p>annotation-xml 5: <math><semantics><csymbol>Content MathML</csymbol><annotation-xml encoding="application/xhtml+xml"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>application/xhtml+xml</title></head><body><p>application/xhtml+xml</p></body></html></annotation-xml><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml><annotation>error</annotation></math></p>
+  <p>annotation-xml 6: <math><semantics><csymbol>Content MathML</csymbol><annotation-xml encoding="text/html"><html><head><title>text/html</title></head><body><p>text/html</p></body></html></annotation-xml><annotation-xml encoding="application/mathml-presentation+xml"><mtext>error</mtext></annotation-xml><annotation>error</annotation></semantics></math></p>
+  <p>annotation-xml 7: <math><semantics><csymbol>Content MathML</csymbol><annotation-xml encoding="unknown"><mtext>error</mtext></annotation-xml><annotation-xml encoding="application/mathml-presentation+xml"><mtext>annotation-xml</mtext></annotation-xml><annotation>error</annotation></semantics></math></p>
+</body>
+</html>
diff --git a/layout/reftests/mathml/semantics-5-ref.html b/layout/reftests/mathml/semantics-5-ref.html
new file mode 100644
index 0000000000..9184cdcc81
--- /dev/null
+++ b/layout/reftests/mathml/semantics-5-ref.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>semantics - embellished operator (bug 21479)</title>
+  <meta charset="utf-8"/>
+</head>
+<body>
+  <p>
+    <math xmlns="http://www.w3.org/1998/Math/MathML">
+      <mover>
+        <mspace width="300px" height="10px" mathbackground="black"></mspace>
+        <mo>&#xaf;</mo>
+      </mover>
+    </math>
+  </p>
+</body>
+</html>
diff --git a/layout/reftests/mathml/semantics-5.html b/layout/reftests/mathml/semantics-5.html
new file mode 100644
index 0000000000..0c2ad9541a
--- /dev/null
+++ b/layout/reftests/mathml/semantics-5.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>semantics - embellished operator (bug 21479)</title>
+  <meta charset="utf-8"/>
+</head>
+<body>
+  <p>
+    <math xmlns="http://www.w3.org/1998/Math/MathML">
+      <mover>
+        <mspace width="300px" height="10px" mathbackground="black"></mspace>
+        <semantics><mo>&#xaf;</mo></semantics>
+      </mover>
+    </math>
+  </p>
+</body>
+</html>
diff --git a/layout/reftests/mathml/stretchy-1-ref.html b/layout/reftests/mathml/stretchy-1-ref.html
new file mode 100644
index 0000000000..23950c02fa
--- /dev/null
+++ b/layout/reftests/mathml/stretchy-1-ref.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test stretchy equal (bug 854339)</title></head>
+  <body>
+
+    <math>
+      <munder>
+        <mi>AVERYLONGBASE</mi>
+        <mo stretchy="false">=</mo>
+      </munder>
+    </math>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/stretchy-1.html b/layout/reftests/mathml/stretchy-1.html
new file mode 100644
index 0000000000..d4cfcb24f5
--- /dev/null
+++ b/layout/reftests/mathml/stretchy-1.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+  <head><title>Test stretchy equal (bug 854339)</title></head>
+  <body>
+
+    <math>
+      <munder>
+        <mi>AVERYLONGBASE</mi>
+        <mo stretchy="true">=</mo>
+      </munder>
+    </math>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/stretchy-largeop-1-ref.html b/layout/reftests/mathml/stretchy-largeop-1-ref.html
new file mode 100644
index 0000000000..b65a38958f
--- /dev/null
+++ b/layout/reftests/mathml/stretchy-largeop-1-ref.html
@@ -0,0 +1,56 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Largeop stretching</title>
+    <meta charset="utf-8"/>
+  </head>
+  <body>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mo id="mo0">(</mo>
+          <mo>∫</mo>
+          <mo id="mo1">)</mo>
+        <mrow>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mrow>
+          <mo id="mo0a">(</mo>
+          <mo>∫</mo>
+          <mo id="mo1a">)</mo>
+        <mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mo id="mo2">(</mo>
+          <mo>&Product;</mo>
+          <mo id="mo3">)</mo>
+        <mrow>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mrow>
+          <mo id="mo2a">(</mo>
+          <mo>&Product;</mo>
+          <mo id="mo3a">)</mo>
+        <mrow>
+      </math>
+    </p>
+    <p>
+      <!-- &bigotimes; included in the test to check for an assertion involving
+           the direction of the largeop pre-stretch -->
+      <math displaystyle="true">
+        <mrow>
+          <mo id="mo4">(</mo>
+          <mo>&bigotimes;</mo>
+          <mo id="mo5">)</mo>
+        <mrow>
+      </math>
+    </p>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/stretchy-largeop-1.html b/layout/reftests/mathml/stretchy-largeop-1.html
new file mode 100644
index 0000000000..bb63c8a435
--- /dev/null
+++ b/layout/reftests/mathml/stretchy-largeop-1.html
@@ -0,0 +1,81 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+  <head>
+    <title>Largeop stretching</title>
+    <meta charset="utf-8"/>
+    <script type="text/javascript">
+
+      function verifyGreaterThan(aElement, aReference) {
+        /* Verify that the height of the element is greater than that of the
+           reference, and otherwise paint the element in red. */
+        var element = document.getElementById(aElement);
+        var ref = document.getElementById(aReference);
+        if (element.getBoundingClientRect().height -
+            ref.getBoundingClientRect().height <= 1) {
+          element.setAttribute("mathcolor", "red");
+        }
+      }
+
+      function doTest() {
+        /* Ensure that the parentheses in the displaystyle case stretch more
+           than the alternative. */
+        verifyGreaterThan("mo0", "mo0a");
+        verifyGreaterThan("mo1", "mo1a");
+        verifyGreaterThan("mo2", "mo2a");
+        verifyGreaterThan("mo3", "mo3a");
+
+        document.documentElement.removeAttribute("class");
+
+      }
+    </script>
+  </head>
+  <body onload="doTest();">
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mo id="mo0">(</mo>
+          <mo>∫</mo>
+          <mo id="mo1">)</mo>
+        <mrow>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mrow>
+          <mo id="mo0a">(</mo>
+          <mo>∫</mo>
+          <mo id="mo1a">)</mo>
+        <mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mo id="mo2">(</mo>
+          <mo>&Product;</mo>
+          <mo id="mo3">)</mo>
+        <mrow>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mrow>
+          <mo id="mo2a">(</mo>
+          <mo>&Product;</mo>
+          <mo id="mo3a">)</mo>
+        <mrow>
+      </math>
+    </p>
+    <p>
+      <!-- &bigotimes; included in the test to check for an assertion involving
+           the direction of the largeop pre-stretch -->
+      <math displaystyle="true">
+        <mrow>
+          <mo id="mo4">(</mo>
+          <mo>&bigotimes;</mo>
+          <mo id="mo5">)</mo>
+        <mrow>
+      </math>
+    </p>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/stretchy-largeop-2-ref.html b/layout/reftests/mathml/stretchy-largeop-2-ref.html
new file mode 100644
index 0000000000..d06d26527b
--- /dev/null
+++ b/layout/reftests/mathml/stretchy-largeop-2-ref.html
@@ -0,0 +1,111 @@
+<!DOCTYPE html>
+<!-- Test that non-stretchy largeops are bigger in display mode -->
+
+<html>
+  <head>
+    <title>Largeop stretching</title>
+    <meta charset="utf-8"/>
+  </head>
+  <body>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo0">&bigodot;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo1">&bigoplus;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo2">&#x2a03;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo3">&#x2a05;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo4">&#x2a07;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo5">&#x2a08;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo6">&#x2a09;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo7">&#x2a0a;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo8">&#x2afc;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo9">&#x2aff;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef0">&bigodot;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef1">&bigoplus;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef2">&#x2a03;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef3">&#x2a05;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef4">&#x2a07;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef5">&#x2a08;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef6">&#x2a09;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef7">&#x2a0a;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef8">&#x2afc;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef9">&#x2aff;</mo>
+      </math>
+    </p>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/stretchy-largeop-2.html b/layout/reftests/mathml/stretchy-largeop-2.html
new file mode 100644
index 0000000000..c7f40580ec
--- /dev/null
+++ b/layout/reftests/mathml/stretchy-largeop-2.html
@@ -0,0 +1,137 @@
+<!DOCTYPE html>
+<!-- Test that non-stretchy largeops are bigger in display mode -->
+
+<html class="reftest-wait">
+  <head>
+    <title>Largeop stretching</title>
+    <meta charset="utf-8"/>
+    <script type="text/javascript">
+
+      function verifyGreaterThan(aElement, aReference) {
+        /* Verify that the height of the element is greater than that of the
+           reference, and otherwise paint the element in red. */
+        var element = document.getElementById(aElement);
+        var ref = document.getElementById(aReference);
+        if (element.getBoundingClientRect().height -
+            ref.getBoundingClientRect().height <= 1) {
+          element.setAttribute("mathcolor", "red");
+        }
+      }
+
+      function doTest() {
+        /* Ensure that largeops are bigger in displaystyle */
+        var numTests = 10; // zero indexed
+        var opPrefix = "mo";
+        var refPrefix = "moRef";
+        for (var i = 0; i < numTests; i++)
+        {
+          verifyGreaterThan(opPrefix + i, refPrefix + i);
+        }
+        document.documentElement.removeAttribute("class");
+
+      }
+    </script>
+  </head>
+  <body onload="doTest();">
+    <p>
+      <math displaystyle="true">
+        <mo id="mo0">&bigodot;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo1">&bigoplus;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo2">&#x2a03;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo3">&#x2a05;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo4">&#x2a07;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo5">&#x2a08;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo6">&#x2a09;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo7">&#x2a0a;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo8">&#x2afc;</mo>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="mo9">&#x2aff;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef0">&bigodot;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef1">&bigoplus;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef2">&#x2a03;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef3">&#x2a05;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef4">&#x2a07;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef5">&#x2a08;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef6">&#x2a09;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef7">&#x2a0a;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef8">&#x2afc;</mo>
+      </math>
+    </p>
+    <p>
+      <math>
+        <mo id="moRef9">&#x2aff;</mo>
+      </math>
+    </p>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/stretchy-largeop-3-ref.html b/layout/reftests/mathml/stretchy-largeop-3-ref.html
new file mode 100644
index 0000000000..83837c8b30
--- /dev/null
+++ b/layout/reftests/mathml/stretchy-largeop-3-ref.html
@@ -0,0 +1,123 @@
+<!DOCTYPE html>
+<!-- Test that non-stretchy largeops do not stretch -->
+
+<html>
+  <head>
+    <title>Largeop stretching</title>
+    <meta charset="utf-8" />
+  </head>
+   <body>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo0">&bigodot;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo1">&bigoplus;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo2">&#x2a03;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo3">&#x2a05;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo4">&#x2a07;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo5">&#x2a08;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo6">&#x2a09;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo7">&#x2a0a;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo8">&#x2afc;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo9">&#x2aff;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="moRef0">&bigodot;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef1">&bigoplus;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef2">&#x2a03;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef3">&#x2a05;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef4">&#x2a07;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef5">&#x2a08;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef6">&#x2a09;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef7">&#x2a0a;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef8">&#x2afc;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef9">&#x2aff;</mo>
+      </math>
+    </p>
+  </body>
+</html>
\ No newline at end of file
diff --git a/layout/reftests/mathml/stretchy-largeop-3.html b/layout/reftests/mathml/stretchy-largeop-3.html
new file mode 100644
index 0000000000..5fe3149894
--- /dev/null
+++ b/layout/reftests/mathml/stretchy-largeop-3.html
@@ -0,0 +1,156 @@
+<!DOCTYPE html>
+<!-- Test that non-stretchy largeops do not stretch -->
+
+<html class="reftest-wait">
+  <head>
+    <title>Largeop stretching</title>
+    <meta charset="utf-8" />
+    <script type="text/javascript">
+
+      function almostEqual(aX, aY) {
+        var epsilon = 2;
+        return Math.abs(aX - aY) < epsilon;
+      }
+
+      function verifySize(aElement, aReference) {
+        /* Verify if the size of the element matches the reference, and
+           otherwise paint the element in red. */
+        var element = document.getElementById(aElement);
+        var ref = document.getElementById(aReference);
+        if (!almostEqual(element.getBoundingClientRect().height,
+                         ref.getBoundingClientRect().height) ||
+            !almostEqual(element.getBoundingClientRect().width,
+                         ref.getBoundingClientRect().width)) {
+          element.setAttribute("mathcolor", "red");
+        }
+      }
+
+      function doTest() {
+        /* Ensure that largeops are bigger in displaystyle */
+        var numTests = 10; // zero indexed
+        var opPrefix = "mo";
+        var refPrefix = "moRef";
+        for (var i = 0; i < numTests; i++)
+        {
+          verifySize(opPrefix + i, refPrefix + i);
+        }
+        document.documentElement.removeAttribute("class");
+
+      }
+    </script>
+  </head>
+  <body onload="doTest();">
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo0">&bigodot;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo1">&bigoplus;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo2">&#x2a03;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo3">&#x2a05;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo4">&#x2a07;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo5">&#x2a08;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo6">&#x2a09;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo7">&#x2a0a;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo8">&#x2afc;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mrow>
+          <mspace height="3em" />
+          <mo id="mo9">&#x2aff;</mo>
+        </mrow>
+      </math>
+    </p>
+    <p>
+      <math displaystyle="true">
+        <mo id="moRef0">&bigodot;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef1">&bigoplus;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef2">&#x2a03;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef3">&#x2a05;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef4">&#x2a07;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef5">&#x2a08;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef6">&#x2a09;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef7">&#x2a0a;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef8">&#x2afc;</mo>
+      </math>
+      <math displaystyle="true">
+        <mo id="moRef9">&#x2aff;</mo>
+      </math>
+    </p>
+  </body>
+</html>
diff --git a/layout/reftests/mathml/subscript-italic-correction-ref.html b/layout/reftests/mathml/subscript-italic-correction-ref.html
new file mode 100644
index 0000000000..a4527325cd
--- /dev/null
+++ b/layout/reftests/mathml/subscript-italic-correction-ref.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>subscript</title>
+    <meta charset="utf-8"/>
+  </head>
+  <body style="background: #5f5; font-size: 50px;">
+
+    <div>
+      <math>
+        <msubsup>
+          <mi mathbackground="#5f5">f</mi>
+          <mspace id="s0" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s1" width="50px" height="50px" mathbackground="blue"/>
+        </msubsup>
+      </math>
+    </div>
+
+    <br/>
+
+    <div>
+      <math>
+        <mmultiscripts>
+          <mi mathbackground="#5f5">f</mi>
+          <mspace id="s2" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s3" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s4" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s5" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s6" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s7" width="50px" height="50px" mathbackground="blue"/>
+        </mmultiscripts>
+      </math>
+    </div>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/subscript-italic-correction.html b/layout/reftests/mathml/subscript-italic-correction.html
new file mode 100644
index 0000000000..04be7ba5f9
--- /dev/null
+++ b/layout/reftests/mathml/subscript-italic-correction.html
@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+  <head>
+    <title>subscript</title>
+    <meta charset="utf-8"/>
+    <script type="text/javascript">
+      function verifyItalicCorrections()
+      {
+        var epsilon = 2;
+        for (var i = 0; i < 8; i += 2) {
+          var sub = document.getElementById("s" + i);
+          var sup = document.getElementById("s" + (i+1));
+          var italicCorrection =
+           sup.getBoundingClientRect().left - sub.getBoundingClientRect().left;
+           if (italicCorrection < epsilon) {
+             return false;
+           }
+        }
+        return true;
+      }
+
+      function doTest()
+      {
+        if (verifyItalicCorrections()) {
+          document.body.style.background = "#5f5";
+        }
+        document.documentElement.removeAttribute("class");
+      }
+      window.addEventListener("MozReftestInvalidate", doTest);
+    </script>
+  </head>
+  <body style="background: #f00; font-size: 50px;">
+
+    <div>
+      <math>
+        <msubsup>
+          <mi mathbackground="#5f5">f</mi>
+          <mspace id="s0" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s1" width="50px" height="50px" mathbackground="blue"/>
+        </msubsup>
+      </math>
+    </div>
+
+    <br/>
+
+    <div>
+      <math>
+        <mmultiscripts>
+          <mi mathbackground="#5f5">f</mi>
+          <mspace id="s2" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s3" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s4" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s5" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s6" width="50px" height="50px" mathbackground="blue"/>
+          <mspace id="s7" width="50px" height="50px" mathbackground="blue"/>
+        </mmultiscripts>
+      </math>
+    </div>
+
+  </body>
+</html>
diff --git a/layout/reftests/mathml/underbar-width-1-ref.xhtml b/layout/reftests/mathml/underbar-width-1-ref.xhtml
new file mode 100644
index 0000000000..737673ccb1
--- /dev/null
+++ b/layout/reftests/mathml/underbar-width-1-ref.xhtml
@@ -0,0 +1,26 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <style type="text/css">
+      html { background-color: grey; }
+      div { display: inline-block;
+            font-size: 30px;
+            line-height: 60px; /* Ensure space for underbar */
+            border: 1px solid white;
+            padding: 2px; /* 10% error allowed in char selection */
+            background-color: black;
+            color: red; }
+    </style>
+  </head>
+<body>
+  <div>
+    <math xmlns="http://www.w3.org/1998/Math/MathML">
+      <mphantom>
+	<munder>
+	  <mn>1</mn>
+	  <mo>&#x332;</mo>
+	</munder>
+      </mphantom>
+    </math>
+  </div>
+</body>
+</html>
diff --git a/layout/reftests/mathml/underbar-width-1.xhtml b/layout/reftests/mathml/underbar-width-1.xhtml
new file mode 100644
index 0000000000..473b25b91d
--- /dev/null
+++ b/layout/reftests/mathml/underbar-width-1.xhtml
@@ -0,0 +1,25 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>Check width of stretchy OverBar</title>
+    <style type="text/css">
+      html { background-color: grey; }
+      div { display: inline-block;
+            font-size: 30px;
+            line-height: 60px; /* Ensure space for underbar */
+            border: 1px solid white;
+            padding: 2px; /* 10% error allowed in char selection */
+            background-color: black;
+            color: black; }
+    </style>
+  </head>
+<body>
+  <div>
+    <math xmlns="http://www.w3.org/1998/Math/MathML">
+      <munder>
+	<mn>1</mn>
+	<mo>&#x332;</mo>
+      </munder>
+    </math>
+  </div>
+</body>
+</html>
-- 
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