public RadForm1()
        {
            InitializeComponent(); 
            this.radBreadCrumb1.DefaultTreeView = this.radTreeView1; 
            this.radBreadCrumb1.SplitButtonCreated+=radBreadCrumb1_SplitButtonCreated;
        }

        private void radBreadCrumb1_SplitButtonCreated(object sender, Telerik.WinControls.UI.BreadCrumb.SplitButtonCreatedEventArgs e)
        {
            foreach (RadTreeNode n in e.AssociatedTreeNode.Nodes)
            {
                if (n.Visible==false)
                {
                    e.SplitButtonElement.Items[n.Index].Visibility = ElementVisibility.Collapsed;
                }
            }
        }