diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug685692.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug685692.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,48 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  waitForExplicitFinish();
+
+  newWindowWithTabView(win => {
+    win.gBrowser.addTab("http://example.com/");
+    win.gBrowser.addTab("http://example.com/");
+
+    afterAllTabsLoaded(function() {
+      let cw = win.TabView.getContentWindow();
+
+      let groupItemOne = cw.GroupItems.groupItems[0];
+      is(groupItemOne.getChildren().length, 3, "The number of tabs in group one is 3");
+
+      // create a group with a blank tab
+      let groupItemTwo = createGroupItemWithBlankTabs(win, 400, 400, 40, 1);
+      is(groupItemTwo.getChildren().length, 1, "The number of tabs in group two is 1");
+
+      cw.UI.setActive(groupItemOne);
+
+      moveTabToAnotherGroup(win, groupItemOne.getChild(2).tab, groupItemOne, groupItemTwo, function() {
+        moveTabToAnotherGroup(win, groupItemOne.getChild(1).tab, groupItemOne, groupItemTwo, function() {
+          groupItemOne.close();
+          promiseWindowClosed(win).then(finish);
+        });
+      });
+    });
+  });
+}
+
+function moveTabToAnotherGroup(win, targetTab, groupItemOne, groupItemTwo, callback) {
+  hideTabView(function() {
+    let tabCountInGroupItemOne = groupItemOne.getChildren().length;
+    let tabCountInGroupItemTwo = groupItemTwo.getChildren().length;
+
+    win.TabView.moveTabTo(targetTab, groupItemTwo.id);
+
+    showTabView(function() {
+      is(groupItemOne.getChildren().length, --tabCountInGroupItemOne, "The number of tab items in group one is decreased");
+      is(groupItemTwo.getChildren().length, ++tabCountInGroupItemTwo, "The number of tab items in group two is increased");
+      is(groupItemTwo.getChild(tabCountInGroupItemTwo-1).tab, targetTab, "The last tab is the moved tab");
+
+      callback();
+    }, win);
+  }, win);
+}