WB3D forced repaint event?

Shame, it didn't work. Well, that is, I can't seem to call this api_InvalidateRect() without getting a Memory Access Violation..

I've tried:
api_InvalidateRect( SystemProperty("AppHwnd") , 0, True )
api_InvalidateRect( SystemProperty("AppHwnd") , null, True )

with user32.decls:
api_InvalidateRect% (hwnd%, lpRect*, bErase%) : "InvalidateRect"

:(