private void FlexChart1_MouseDown(object sender, MouseButtonEventArgs e)
        {
            var ht = flexChart.HitTest(e.GetPosition(flexChart));
            if (ht != null)
            {
                if (ht.Distance == 0)
                {
                    //Do your stuff
                    var msg = "";
                    msg += "Series Symbol Clicked : ";
                    msg += (ht.Item as Product).Name + "(" + (ht.Item as Product).Price + ")";
                    MessageBox.Show(msg);
                }
            }
        }