diff -r 000000000000 -r 6474c204b198 browser/components/customizableui/test/browser_981418-widget-onbeforecreated-handler.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/customizableui/test/browser_981418-widget-onbeforecreated-handler.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,90 @@
+/* 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-981418-widget-onbeforecreated';
+
+// Should be able to add broken view widget
+add_task(function testAddOnBeforeCreatedWidget() {
+  let viewShownDeferred = Promise.defer();
+  let onBeforeCreatedCalled = false;
+  let widgetSpec = {
+    id: kWidgetId,
+    type: 'view',
+    viewId: kWidgetId + 'idontexistyet',
+    onBeforeCreated: function(doc) {
+      let view = doc.createElement("panelview");
+      view.id = kWidgetId + 'idontexistyet';
+      let label = doc.createElement("label");
+      label.setAttribute("value", "Hello world");
+      label.className = 'panel-subview-header';
+      view.appendChild(label);
+      document.getElementById("PanelUI-multiView").appendChild(view);
+      onBeforeCreatedCalled = true;
+    },
+    onViewShowing: function() {
+      viewShownDeferred.resolve();
+    }
+  };
+
+  let noError = true;
+  try {
+    CustomizableUI.createWidget(widgetSpec);
+    CustomizableUI.addWidgetToArea(kWidgetId, CustomizableUI.AREA_NAVBAR);
+  } catch (ex) {
+    Cu.reportError(ex);
+    noError = false;
+  }
+  ok(noError, "Should not throw an exception trying to add the widget.");
+  ok(onBeforeCreatedCalled, "onBeforeCreated should have been called");
+
+  let widgetNode = document.getElementById(kWidgetId);
+  ok(widgetNode, "Widget should exist");
+  if (widgetNode) {
+    try {
+      widgetNode.click();
+
+      let shownTimeout = setTimeout(() => viewShownDeferred.reject("Panel not shown within 20s"), 20000);
+      yield viewShownDeferred.promise;
+      clearTimeout(shownTimeout);
+      ok(true, "Found view shown");
+
+      let tempPanel = document.getElementById("customizationui-widget-panel");
+      let panelHiddenPromise = promisePanelElementHidden(window, tempPanel);
+      tempPanel.hidePopup();
+      yield panelHiddenPromise;
+
+      CustomizableUI.addWidgetToArea(kWidgetId, CustomizableUI.AREA_PANEL);
+      yield PanelUI.show();
+
+      viewShownDeferred = Promise.defer();
+      widgetNode.click();
+
+      shownTimeout = setTimeout(() => viewShownDeferred.reject("Panel not shown within 20s"), 20000);
+      yield viewShownDeferred.promise;
+      clearTimeout(shownTimeout);
+      ok(true, "Found view shown");
+
+      let panelHidden = promisePanelHidden(window);
+      PanelUI.hide();
+      yield panelHidden;
+    } catch (ex) {
+      ok(false, "Unexpected exception (like a timeout for one of the yields) " +
+                "when testing view widget.");
+    }
+  }
+
+  noError = true;
+  try {
+    CustomizableUI.destroyWidget(kWidgetId);
+  } catch (ex) {
+    Cu.reportError(ex);
+    noError = false;
+  }
+  ok(noError, "Should not throw an exception trying to remove the broken view widget.");
+});
+
+add_task(function asyncCleanup() {
+  yield resetCustomization();
+});