http://bugs.winehq.org/show_bug.cgi?id=16430
Dan Kegel dank@kegel.com changed:
What |Removed |Added ---------------------------------------------------------------------------- CC| |dank@kegel.com
--- Comment #7 from Dan Kegel dank@kegel.com 2009-01-16 19:37:22 --- winuser.h says #define WM_APP 0x8000 so your 0xc099 message is probably from the app rather than from windows.
So your patch probably isn't correct. It would be interesting to follow that message on Windows and see who sends it and who intercepts it...