private void IMenuBuilder.MenuItemClicked(IMenuItem MenuItem) //<-- _
  implementierte Function
        {
            if (MenuItem != null)
            {
                try
                {
                    MenuItem.Execute();
                }
                catch (System.Exception ex)
                {
                                    }
            }
        }

private void TreeItemClicked(object sender, System.Windows.Forms.MouseEventArgs _
  e)
        {
            UltraTree TreeNodeFromSender = (UltraTree)sender;
 
            if (TreeNodeFromSender.ActiveNode.DataKey != null)
            {
                IMenuItem MenuItem = ( _
                  IMenuItem)TreeNodeFromSender.ActiveNode.DataKey;
                MenuItemClicked MenuItem; //hier soll der aufruf _
                erfolgen            }
        }