protected override void WndProc(ref Message m)
 {
     switch (m.Msg)
     {
     case 0x00000020:     // WM_SETCURSOR
         if (OverrideCursor)
         {
             if (Root.Instance.RenderSystem != null)
             {
                 Root.Instance.RenderSystem.RestoreCursor();
                 m.Result = new IntPtr(1);     // return TRUE;
                 return;
             }
         }
         break;
     }
     if (!DefaultForm.WndOverride(ref m))
     {
         base.WndProc(ref m);
     }
 }