Forcing full redraw of form background

Question

Hi.

I've created a form which uses controls with transparent edges. The problem I'm now facing is that the cleverness of the .net Compact framework makes sure that the background (The form area beneath the control) isn't drawn since it believes that this won't be visible. This results in the rather interesting, but ugly, result that the transparent areas of the control shows whatever was visible in the background when the app was launched.

Is there any way of forcing a form to repaint itself completely? Including the areas it assumes won't be visible?