Change RadFormTitleBarElement default context menu

  public partial class RadForm1 : Telerik.WinControls.UI.RadForm
    {
        public RadForm1()
        {
            InitializeComponent(); 
        }

        public const int WM_CONTEXTMENU = 0x7b;
         

        protected override void WndProc(ref System.Windows.Forms.Message m)
        { 
            if (m.Msg == WM_CONTEXTMENU)
            {
                RadContextMenu menu = new RadContextMenu();

                RadMenuItem item = new RadMenuItem("Restore");
                item.Click += new EventHandler(item_Click);
                menu.Items.Add(item);

                RadMenuItem item1 = new RadMenuItem("Maximize");
                item1.Click += new EventHandler(item1_Click);
                menu.Items.Add(item1);

                RadMenuItem item2 = new RadMenuItem("Minimize");
                item2.Click += new EventHandler(item2_Click);
                menu.Items.Add(item2);

                menu.Show(this, PointToClient(Control.MousePosition));

                return;
            }

            base.WndProc(ref m);
        }

        void item1_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Maximized;
        }

        void item_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Normal;
        }

        void item2_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
        }
    }