diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug622835.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug622835.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,44 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  waitForExplicitFinish();
+
+  newWindowWithTabView(onTabViewShown);
+}
+
+function onTabViewShown(win) {
+  let contentWindow = win.TabView.getContentWindow();
+
+  let finishTest = function () {
+    hideTabView(function () {
+      win.close();
+      finish();
+    }, win);
+  }
+
+  // do not let the group arrange itself
+  contentWindow.GroupItems.pauseArrange();
+
+  // let's create a groupItem small enough to get stacked
+  let groupItem = new contentWindow.GroupItem([], {
+    immediately: true,
+    bounds: {left: 20, top: 20, width: 100, height: 100}
+  });
+
+  contentWindow.UI.setActive(groupItem);
+
+  // we need seven tabs at least to reproduce this
+  for (var i=0; i<7; i++)
+    win.gBrowser.loadOneTab('about:blank', {inBackground: true});
+
+  // finally let group arrange
+  contentWindow.GroupItems.resumeArrange();
+
+  let tabItem6 = groupItem.getChildren()[5];
+  let tabItem7 = groupItem.getChildren()[6];  
+  ok(!tabItem6.getHidden(), 'the 6th child must not be hidden');
+  ok(tabItem7.getHidden(), 'the 7th child must be hidden');
+
+  finishTest();
+}