The Folder icon should be highlight in the Menu items.

public RadForm1()
{
    InitializeComponent();

    this.radTreeView1.HotTracking = false;
    this.radTreeView1.CreateNodeElement+=radTreeView1_CreateNodeElement;

    this.radTreeView1.DisplayMember = "name";
    this.radTreeView1.ParentMember = "pid";
    this.radTreeView1.ChildMember = "id";
    this.radTreeView1.DataSource = this.GetSampleData();
}

private void radTreeView1_CreateNodeElement(object sender, CreateTreeNodeElementEventArgs e)
{
    e.NodeElement = new CustomTreeNodeElement();
}

private DataTable GetSampleData()
{
    DataTable dt = new DataTable();

    DataColumn dc = new DataColumn();
    dc.ColumnName = "id";
    dc.DataType = typeof(int);
    dt.Columns.Add(dc);

    DataColumn dc1 = new DataColumn();
    dc1.ColumnName = "name";
    dc1.DataType = typeof(string);
    dt.Columns.Add(dc1);

    DataColumn dc2 = new DataColumn();
    dc2.ColumnName = "pid";
    dc2.DataType = typeof(int);
    dt.Columns.Add(dc2);

    DataRow dr = dt.NewRow();
    dr[0] = 0;
    dr[1] = "My Computer";
    dr[2] = DBNull.Value;
    dt.Rows.Add(dr);

    dr = dt.NewRow();
    dr[0] = 1;
    dr[1] = @"C:\";
    dr[2] = 0;
    dt.Rows.Add(dr);

    dr = dt.NewRow();
    dr[0] = 2;
    dr[1] = @"D:\";
    dr[2] = 0;
    dt.Rows.Add(dr);

    dr = dt.NewRow();
    dr[0] = 3;
    dr[1] = "Program Files";
    dr[2] = 1;
    dt.Rows.Add(dr);

    dr = dt.NewRow();
    dr[0] = 4;
    dr[1] = "Microsoft";
    dr[2] = 3;
    dt.Rows.Add(dr);

    dr = dt.NewRow();
    dr[0] = 5;
    dr[1] = "Telerik";
    dr[2] = 3;
    dt.Rows.Add(dr);

    dr = dt.NewRow();
    dr[0] = 6;
    dr[1] = "WINDOWS";
    dr[2] = 1;
    dt.Rows.Add(dr);

    return dt;
}

classCustomContentElement : TreeNodeContentElement
{
    StackLayoutElement stack = new StackLayoutElement();
    RadToggleButtonElement button = new RadToggleButtonElement();
    LightVisualElement text = new LightVisualElement();

    protectedoverride Type ThemeEffectiveType
    {
        get
        {
            returntypeof(TreeNodeContentElement);
        }
    }

    protected override void CreateChildElements()
    {
        base.CreateChildElements();
        stack.Orientation = Orientation.Horizontal;
        stack.StretchHorizontally = true;
        stack.Children.Add(button);
        stack.Children.Add(text);
        button.ToggleStateChanged+=button_ToggleStateChanged;
      
        button.MaxSize= button.MinSize = new System.Drawing.Size(30, 0);
        text.StretchHorizontally = true;
        this.Children.Add(stack);
    }

    private void button_ToggleStateChanged(object sender, StateChangedEventArgs args)
    {
        this.NodeElement.Data.Tag = args.ToggleState;
    }

    public override void Synchronize()
    {
        base.Synchronize();
        button.Image = Properties.Resources.InboxFolder;
        button.ImageAlignment = ContentAlignment.MiddleCenter;
        this.DrawText = false;
        text.Text = this.NodeElement.Data.Text;

          button.ToggleStateChanged-=button_ToggleStateChanged;
        button.ToggleState = ToggleState.Off;
         if (this.NodeElement.Data.Tag !=null )
          {
              button.ToggleState = (ToggleState)this.NodeElement.Data.Tag;
          }
          button.ToggleStateChanged+=button_ToggleStateChanged;
    }
}

publicclassCustomTreeNodeElement : TreeNodeElement
{
    protected override TreeNodeContentElement CreateContentElement()
    {
        returnnew CustomContentElement();
    }
    
    protectedoverride Type ThemeEffectiveType
    {
        get
        {
            returntypeof(TreeNodeElement);
        }
    }
}