function clearNotificationBar(oShell) {
			var oOldNotificationBar = oShell.getNotificationBar();
			if (oOldNotificationBar) {
				oShell._setNotifyVisibility(NotificationBarStatus.None);
				oOldNotificationBar.setVisibleStatus = oOldNotificationBar.__orig_setVisibleStatus;
				oOldNotificationBar.detachDisplay(oOldNotificationBar.__fHandleNotifyDisplay);
				delete oOldNotificationBar.__orig_setVisibleStatus;
				delete oOldNotificationBar.__fHandleNotifyDisplay;
			}
		}
Focuses the last element in the tab chain which belongs to the Shell Pane. This is also the "last" element of the Shell.

@private