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