public void HideFocusCues(Control control)
{
 Type vType = typeof(Control);
 FieldInfo vFieldInfo = vType.GetField("uiCuesState",
  BindingFlags.Instance | BindingFlags.Public |
  BindingFlags.NonPublic | BindingFlags.Static |
  BindingFlags.FlattenHierarchy);
 vFieldInfo.SetValue(control, 15);
}
void rbt_Paint(object sender, PaintEventArgs e)
{
 HideFocusCues((Control)sender);
}