/// <summary>
 /// Moves selected element to up
 /// </summary>
 public void MoveUp()
 {
     if (this.handlerCol != null)
     {
         handlerCol.MoveUp();
     }
     if (this.selectedElement != null)
     {
         this.StoreInBuffer(BufferOperation.Update, this.selectedElement);
         selectedElement.MoveUp();
     }
 }