diff -r 000000000000 -r 6474c204b198 browser/components/customizableui/test/browser_876944_customize_mode_create_destroy.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/customizableui/test/browser_876944_customize_mode_create_destroy.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,56 @@
+/* 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 kTestWidget1 = "test-customize-mode-create-destroy1";
+const kTestWidget2 = "test-customize-mode-create-destroy2";
+
+// Creating and destroying a widget should correctly wrap/unwrap stuff
+add_task(function testWrapUnwrap() {
+  yield startCustomizing();
+  CustomizableUI.createWidget({id: kTestWidget1, label: 'Pretty label', tooltiptext: 'Pretty tooltip'});
+  let elem = document.getElementById(kTestWidget1);
+  let wrapper = document.getElementById("wrapper-" + kTestWidget1);
+  ok(elem, "There should be an item");
+  ok(wrapper, "There should be a wrapper");
+  is(wrapper.firstChild.id, kTestWidget1, "Wrapper should have test widget");
+  is(wrapper.parentNode.id, "customization-palette", "Wrapper should be in palette");
+  CustomizableUI.destroyWidget(kTestWidget1);
+  wrapper = document.getElementById("wrapper-" + kTestWidget1);
+  ok(!wrapper, "There should be a wrapper");
+  let item = document.getElementById(kTestWidget1);
+  ok(!item, "There should no longer be an item");
+});
+
+// Creating and destroying a widget should correctly deal with panel placeholders
+add_task(function testPanelPlaceholders() {
+  let panel = document.getElementById(CustomizableUI.AREA_PANEL);
+  is(panel.querySelectorAll(".panel-customization-placeholder").length, isInWin8() ? 1 : 2, "The number of placeholders should be correct.");
+  CustomizableUI.createWidget({id: kTestWidget2, label: 'Pretty label', tooltiptext: 'Pretty tooltip', defaultArea: CustomizableUI.AREA_PANEL});
+  let elem = document.getElementById(kTestWidget2);
+  let wrapper = document.getElementById("wrapper-" + kTestWidget2);
+  ok(elem, "There should be an item");
+  ok(wrapper, "There should be a wrapper");
+  is(wrapper.firstChild.id, kTestWidget2, "Wrapper should have test widget");
+  is(wrapper.parentNode, panel, "Wrapper should be in panel");
+  is(panel.querySelectorAll(".panel-customization-placeholder").length, isInWin8() ? 3 : 1, "The number of placeholders should be correct.");
+  CustomizableUI.destroyWidget(kTestWidget2);
+  wrapper = document.getElementById("wrapper-" + kTestWidget2);
+  ok(!wrapper, "There should be a wrapper");
+  let item = document.getElementById(kTestWidget2);
+  ok(!item, "There should no longer be an item");
+  yield endCustomizing();
+});
+
+add_task(function asyncCleanup() {
+  yield endCustomizing();
+  try {
+    CustomizableUI.destroyWidget(kTestWidget1);
+  } catch (ex) {}
+  try {
+    CustomizableUI.destroyWidget(kTestWidget2);
+  } catch (ex) {}
+  yield resetCustomization();
+});