private void Histogram_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
if ((allowSelection) && (values != null))
{
int x = 1;
int y = 1;
if ((e.X >= x) && (e.Y >= y) && (e.X < x + width) && (e.Y < y + height))
{
// start selection
tracking = true;
start = (vertical) ? (e.Y - y) : (e.X - x);
this.Capture = true;
}
}
}