diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug663421.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug663421.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,88 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  let win, cw, groupItem;
+
+  function checkNumberOfGroupItems(num) {
+    is(cw.GroupItems.groupItems.length, num, "there are " + num + " groupItems");
+  }
+
+  function next() {
+    if (tests.length)
+      tests.shift()();
+    else
+      finish();
+  }
+
+  // Empty groups should not be closed when toggling Panorama on and off.
+  function test1() {
+    hideTabView(function () {
+      showTabView(function () {
+        checkNumberOfGroupItems(2);
+        next();
+      }, win);
+    }, win);
+  }
+
+  // Groups should not be closed when their last tab is closed outside of Panorama.
+  function test2() {
+    whenTabViewIsHidden(function () {
+      whenTabViewIsShown(function () {
+        checkNumberOfGroupItems(2);
+        next();
+      }, win);
+
+      win.gBrowser.removeTab(win.gBrowser.selectedTab);
+    }, win);
+
+    groupItem.newTab();
+  }
+
+  // Groups should be closed when their last tab is closed.
+  function test3() {
+    whenTabViewIsHidden(function () {
+      showTabView(function () {
+        let tab = win.gBrowser.tabs[1];
+        tab._tabViewTabItem.close();
+        checkNumberOfGroupItems(1);
+        next();
+      }, win);
+    }, win);
+
+    win.gBrowser.addTab();
+  }
+
+  // Groups should be closed when their last tab is dragged out.
+  function test4() {
+    groupItem = createGroupItemWithBlankTabs(win, 200, 200, 20, 1);
+    checkNumberOfGroupItems(2);
+
+    let tab = win.gBrowser.tabs[1];
+    let target = tab._tabViewTabItem.container;
+
+    waitForFocus(function () {
+      EventUtils.synthesizeMouseAtCenter(target, {type: "mousedown"}, cw);
+      EventUtils.synthesizeMouse(target, 600, 5, {type: "mousemove"}, cw);
+      EventUtils.synthesizeMouse(target, 600, 5, {type: "mouseup"}, cw);
+
+      checkNumberOfGroupItems(2);
+      closeGroupItem(cw.GroupItems.groupItems[1], next);
+    }, win);
+  }
+
+  let tests = [test1, test2, test3, test4];
+
+  waitForExplicitFinish();
+
+  newWindowWithTabView(function (aWin) {
+    registerCleanupFunction(function () aWin.close());
+
+    win = aWin;
+    cw = win.TabView.getContentWindow();
+    groupItem = createEmptyGroupItem(cw, 200, 200, 20);
+
+    checkNumberOfGroupItems(2);
+    next();
+  });
+}