diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug673729.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug673729.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,42 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  waitForExplicitFinish();
+
+  newWindowWithTabView(function (win) {
+    let cw = win.TabView.getContentWindow();
+
+    // turn off zoom animations
+    cw.gPrefBranch.setBoolPref("animate_zoom", false);
+
+    registerCleanupFunction(function () {
+      cw.gPrefBranch.clearUserPref("animate_zoom");
+      win.close();
+    });
+
+    let group = cw.GroupItems.groupItems[0];
+    group.setSize(100, 100, true);
+
+    while (!group.isStacked())
+      win.gBrowser.addTab();
+
+    waitForFocus(function () {
+      whenGroupIsExpanded(group, function () {
+        ok(win.TabView.isVisible(), "tabview is visible");
+        finish();
+      });
+
+      let expander = group.$expander[0];
+      EventUtils.synthesizeMouseAtCenter(expander, {}, cw);
+    }, cw);
+  });
+}
+
+// ----------
+function whenGroupIsExpanded(group, callback) {
+  group.addSubscriber("expanded", function onExpanded() {
+    group.removeSubscriber("expanded", onExpanded);
+    executeSoon(callback);
+  });
+}