1 files changed, 35 insertions, 0 deletions
diff --git a/layout/reftests/web-animations/stacking-context-transform-changing-effect.html b/layout/reftests/web-animations/stacking-context-transform-changing-effect.html
new file mode 100644
index 0000000000..5e3842df36
--- /dev/null
+++ b/layout/reftests/web-animations/stacking-context-transform-changing-effect.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<html class="reftest-wait reftest-no-flush">
+<title>
+  Transform animation creates a stacking context after changing effects
+</title>
+<style>
+span {
+  height: 100px;
+  width: 100px;
+  position: fixed;
+  background: green;
+  top: 50px;
+}
+div {
+  width: 100px;
+  height: 100px;
+  background: blue;
+}
+</style>
+<span></span>
+<div id="test"></div>
+<script>
+  var elem = document.getElementById("test");
+  var anim = elem.animate(null, { duration: 100000 });
+  var newEffect = new KeyframeEffect(elem,
+                                     { transform: ['none', 'none']},
+                                     100000);
+  anim.ready.then(function() {
+    anim.effect = newEffect;
+    requestAnimationFrame(function() {
+      document.documentElement.classList.remove("reftest-wait");
+    });
+  });
+</script>
+</html>