scroller + ptinrect

Hi,

I'm writing a small program in Windows using BP 7.0. And in one of the
windows I use a bitmap as a button with wm_lbuttondown. My problem is
this : it is inside a scrollbar and I know it works if I don't scroll
but when I scroll it confused the "button" is there any way to correct
this problem?

Thanx in advance
{*word*104}Jape