Hi there,

If the AutoRedraw property of the picture box is set to False
(that is the default) you have to do your graphics in the
OnPaint event. If the size gets smaller the Resize event does not
throw a paint event, so if you are scaling your graphics you
have to pay attention to the OnResize event as well.
Even the graphics done in the Activate event goes away when the
picture box needs repaint (try minimize/maximize your dialog)

Marco