diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug654721.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug654721.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,63 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+let state = {
+  windows: [{
+    tabs: [{
+      entries: [{ url: "about:mozilla" }],
+      hidden: true,
+      extData: {"tabview-tab": '{"url":"about:mozilla","groupID":1,"bounds":{"left":20,"top":20,"width":20,"height":20}}'}
+    },{
+      entries: [{ url: "about:mozilla" }],
+      hidden: false,
+      // this is an existing orphan tab from a previous Fx version and we want
+      // to make sure this gets transformed into a group
+      extData: {"tabview-tab": '{"url":"about:mozilla","groupID":0,"bounds":{"left":300,"top":300,"width":200,"height":200}}'},
+    }],
+    selected: 2,
+    extData: {
+      "tabview-groups": '{"nextID":3,"activeGroupId":1}',
+      "tabview-group":
+        '{"1":{"bounds":{"left":20,"top":20,"width":200,"height":200},"id":1}}'
+    }
+  }]
+};
+
+function test() {
+  waitForExplicitFinish();
+
+  newWindowWithState(state, function (win) {
+    registerCleanupFunction(function () win.close());
+
+    showTabView(function () {
+      let cw = win.TabView.getContentWindow();
+      let groupItems = cw.GroupItems.groupItems;
+      is(groupItems.length, 2, "two groupItems");
+
+      let [group1, group2] = groupItems;
+
+      let bounds1 = new cw.Rect(20, 20, 200, 200);
+      ok(bounds1.equals(group1.getBounds()), "bounds for group1 are correct");
+
+      let bounds2 = new cw.Rect(300, 300, 200, 200);
+      ok(bounds2.equals(group2.getBounds()), "bounds for group2 are correct");
+
+      cw.UI.setActive(group2);
+      win.gBrowser.loadOneTab("about:blank", {inBackground: true});
+
+      let tabItem = group2.getChild(0);
+      let target = tabItem.container;
+
+      EventUtils.synthesizeMouse(target, 10, 10, {type: 'mousedown'}, cw);
+      EventUtils.synthesizeMouse(target, 20, -200, {type: 'mousemove'}, cw);
+      EventUtils.synthesizeMouse(target, 10, 10, {type: 'mouseup'}, cw);
+
+      is(groupItems.length, 3, "three groupItems");
+
+      let latestGroup = groupItems[groupItems.length - 1];
+      is(tabItem, latestGroup.getChild(0), "dragged tab has its own groupItem");
+
+      finish();
+    }, win);
+  });
+}