[Bug 10531] Windows Calculator: Color in buttons missing

http://bugs.winehq.org/show_bug.cgi?id=10531

--- Comment #10 from Dmitry Timoshkov   2008-02-17 22:56:00 ---
> So in my current implementation the button sends CDDS_PREPAINT after the frame
> was drawn, but before the label is drawn. If CDRF_SKIPDEFAULT is send in
> response, the label isn't drawn by the control.

There are 3 phases of painting:
1. non-client area (WM_NCPAINT) - caption, border
2. background (WM_ERASEBKGND)
3. client area (WM_PAINT)

You need to add a test case to dlls/user32/tests/msg.c to make sure that your
patch is correct.