1 files changed, 49 insertions, 0 deletions
diff --git a/browser/components/customizableui/test/browser_909779_overflow_toolbars_new_window.js b/browser/components/customizableui/test/browser_909779_overflow_toolbars_new_window.js
new file mode 100644
index 0000000000..bca9a05b94
--- /dev/null
+++ b/browser/components/customizableui/test/browser_909779_overflow_toolbars_new_window.js
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// Resize to a small window, open a new window, check that new window handles overflow properly
+add_task(async function () {
+  let originalWindowWidth = window.outerWidth;
+  let navbar = document.getElementById(CustomizableUI.AREA_NAVBAR);
+  ok(
+    !navbar.hasAttribute("overflowing"),
+    "Should start with a non-overflowing toolbar."
+  );
+  let oldChildCount =
+    CustomizableUI.getCustomizationTarget(navbar).childElementCount;
+  window.resizeTo(kForceOverflowWidthPx, window.outerHeight);
+  await TestUtils.waitForCondition(() => navbar.hasAttribute("overflowing"));
+  ok(navbar.hasAttribute("overflowing"), "Should have an overflowing toolbar.");
+
+  ok(
+    CustomizableUI.getCustomizationTarget(navbar).childElementCount <
+      oldChildCount,
+    "Should have fewer children."
+  );
+  let newWindow = await openAndLoadWindow();
+  let otherNavBar = newWindow.document.getElementById(
+    CustomizableUI.AREA_NAVBAR
+  );
+  await TestUtils.waitForCondition(() =>
+    otherNavBar.hasAttribute("overflowing")
+  );
+  ok(
+    otherNavBar.hasAttribute("overflowing"),
+    "Other window should have an overflowing toolbar."
+  );
+  await promiseWindowClosed(newWindow);
+
+  window.resizeTo(originalWindowWidth, window.outerHeight);
+  await TestUtils.waitForCondition(() => !navbar.hasAttribute("overflowing"));
+  ok(
+    !navbar.hasAttribute("overflowing"),
+    "Should no longer have an overflowing toolbar."
+  );
+});
+
+add_task(async function asyncCleanup() {
+  await resetCustomization();
+});