private void FlexChart1_MouseMove(object sender, MouseEventArgs e)
 {
     if (_clickedItem != null)
     {
         var newY = flexChart1.PointToData(new Point(e.X, e.Y)).Y;
         if (newY > 0 && newY < 10000)
         {
             _clickedItem.Cost = (int)newY;
             flexChart1.Rebind();
         }
     }
 }