private void DrawHorizontalSelection(Point start, Point end, UserControl ctr)
{
// the clipping rectangle in screen coordinates
Rectangle clip = ctr.RectangleToScreen(
new Rectangle(
(int)ps_.PlotAreaBoundingBoxCache.X,
(int)ps_.PlotAreaBoundingBoxCache.Y,
(int)ps_.PlotAreaBoundingBoxCache.Width,
(int)ps_.PlotAreaBoundingBoxCache.Height));
start = ctr.PointToScreen(start);
end = ctr.PointToScreen(end);
ControlPaint.FillReversibleRectangle(
new Rectangle((int)Math.Min(start.X, end.X), (int)clip.Y, (int)Math.Abs(end.X - start.X), (int)clip.Height),
Color.White);
}