private void schedulerControl1_SelectionChanged(object sender, EventArgs e)
 {
     UnsubscribeSelectionEvents();
     gridView1.BeginSelection();
     try {
         gridView1.ClearSelection();
         for (int i = 0; i < schedulerControl1.SelectedAppointments.Count; i++)
         {
             UpdateGridSelection(schedulerControl1.SelectedAppointments[i]);
         }
     } finally {
         gridView1.EndSelection();
         SubscribeSelectionEvents();
     }
 }