private void OnRibbonGroupClusterRemoved(object sender, TypedCollectionEventArgs<KryptonRibbonGroupItem> e)
{
// Remove the back references
e.Item.Ribbon = null;
e.Item.RibbonTab = null;
e.Item.RibbonContainer = null;
// Only need to update display if this tab is selected and the group was visible
if ((Ribbon != null) && (RibbonTab != null) && (Ribbon.SelectedTab == RibbonTab))
Ribbon.PerformNeedPaint(true);
}