diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug649319.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug649319.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,78 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  waitForExplicitFinish();
+
+  newWindowWithTabView(function (win) {
+    registerCleanupFunction(function () win.close());
+    waitForFocus(function () testScenarios(win));
+  });
+}
+
+function testScenarios(win) {
+  let simulateDragDrop = function (target) {
+    EventUtils.synthesizeMouseAtCenter(target, {type: "mousedown"}, cw);
+    EventUtils.synthesizeMouse(target, 40, 20, {type: "mousemove"}, cw);
+    EventUtils.synthesizeMouse(target, 80, 20, {type: "mouseup"}, cw);
+  }
+
+  let dragOutOfGroup = function (target) {
+    EventUtils.synthesizeMouseAtCenter(target, {type: "mousedown"}, cw);
+    EventUtils.synthesizeMouse(target, 600, 5, {type: "mousemove"}, cw);
+    EventUtils.synthesizeMouse(target, 600, 5, {type: "mouseup"}, cw);
+  }
+
+  let dragIntoGroup = function (target) {
+    EventUtils.synthesizeMouseAtCenter(target, {type: "mousedown"}, cw);
+    EventUtils.synthesizeMouse(target, -200, 5, {type: "mousemove"}, cw);
+    EventUtils.synthesizeMouse(target, -200, 5, {type: "mouseup"}, cw);
+  }
+
+  let assertActiveOrphan = function (tabItem) {
+    ok(!cw.GroupItems.getActiveGroupItem(), "no groupItem is active");
+    is(cw.UI.getActiveTab(), tabItem, "orphan tab is active");
+    is(cw.UI.getActiveOrphanTab(), tabItem, "orphan tab is active");
+  }
+
+  let cw = win.TabView.getContentWindow();
+  let groupItem = cw.GroupItems.groupItems[0];
+  let groupItem2 = createGroupItemWithBlankTabs(win, 400, 300, 20, 4);
+
+  // move group
+  cw.UI.setActive(groupItem);
+  simulateDragDrop(groupItem2.container);
+  is(cw.GroupItems.getActiveGroupItem(), groupItem2, "second groupItem is active");
+  is(cw.UI.getActiveTab(), groupItem2.getChild(0), "second groupItem's first tab is active");
+
+  // resize group
+  cw.UI.setActive(groupItem);
+  let tabItem = groupItem2.getChild(2);
+  groupItem2.setActiveTab(tabItem);
+  simulateDragDrop(groupItem2.$resizer[0]);
+  is(cw.GroupItems.getActiveGroupItem(), groupItem2, "second groupItem is active");
+  is(cw.UI.getActiveTab(), tabItem, "second groupItem's third tab is active");
+
+  // drag tab out of group
+  tabItem = groupItem2.getChild(0);
+  dragOutOfGroup(tabItem.container);
+  is(cw.UI.getActiveTab(), tabItem, "the dragged tab is active");
+
+  // drag back into group
+  dragIntoGroup(tabItem.container);
+  cw.UI.setActive(groupItem);
+  cw.UI.setActive(groupItem2);
+  is(cw.UI.getActiveTab(), tabItem, "the dropped tab is active");
+
+  // hide + unhide groupItem
+  hideGroupItem(groupItem2, function () {
+    is(cw.GroupItems.getActiveGroupItem(), groupItem, "first groupItem is active");
+
+    unhideGroupItem(groupItem2, function () {
+      is(cw.GroupItems.getActiveGroupItem(), groupItem2, "second groupItem is active");
+      is(cw.UI.getActiveTab(), tabItem, "the dropped tab is active");
+
+      finish();
+    });
+  });
+}