diff -r 000000000000 -r 6474c204b198 browser/components/customizableui/test/browser_892956_destroyWidget_defaultPlacements.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/customizableui/test/browser_892956_destroyWidget_defaultPlacements.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,24 @@
+/* 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";
+
+const kWidgetId = "test-892956-destroyWidget-defaultPlacement";
+
+// destroyWidget should clean up defaultPlacements if the widget had a defaultArea
+add_task(function() {
+  ok(CustomizableUI.inDefaultState, "Should be in the default state when we start");
+
+  let widgetSpec = {
+    id: kWidgetId,
+    defaultArea: CustomizableUI.AREA_NAVBAR
+  };
+  CustomizableUI.createWidget(widgetSpec);
+  CustomizableUI.destroyWidget(kWidgetId);
+  ok(CustomizableUI.inDefaultState, "Should be in the default state when we finish");
+});
+
+add_task(function asyncCleanup() {
+  yield resetCustomization();
+});