diff -r 000000000000 -r 6474c204b198 toolkit/components/startup/tests/browser/browser_bug537449.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/startup/tests/browser/browser_bug537449.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,45 @@
+/* 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 TEST_URL = "http://example.com/browser/toolkit/components/startup/tests/browser/beforeunload.html";
+
+function test() {
+  waitForExplicitFinish();
+
+  gBrowser.selectedTab = gBrowser.addTab(TEST_URL);
+  let browser = gBrowser.selectedBrowser;
+
+  whenBrowserLoaded(browser, function () {
+    let seenDialog = false;
+
+    // Cancel the prompt the first time.
+    waitForOnBeforeUnloadDialog(browser, (btnLeave, btnStay) => {
+      seenDialog = true;
+      btnStay.click();
+    });
+
+    let appStartup = Cc['@mozilla.org/toolkit/app-startup;1'].
+                       getService(Ci.nsIAppStartup);
+    appStartup.quit(Ci.nsIAppStartup.eAttemptQuit);
+    ok(seenDialog, "Should have seen a prompt dialog");
+    ok(!window.closed, "Shouldn't have closed the window");
+
+    let win2 = window.openDialog(location, "", "chrome,all,dialog=no", "about:blank");
+    ok(win2 != null, "Should have been able to open a new window");
+    win2.addEventListener("load", function onLoad() {
+      win2.removeEventListener("load", onLoad);
+      win2.close();
+
+      // Leave the page the second time.
+      waitForOnBeforeUnloadDialog(browser, (btnLeave, btnStay) => {
+        btnLeave.click();
+      });
+
+      gBrowser.removeTab(gBrowser.selectedTab);
+      executeSoon(finish);
+    });
+  });
+}