http://bugs.winehq.org/show_bug.cgi?id=34315
--- Comment #5 from Lope lopeonline@gmail.com 2013-08-21 12:22:54 CDT --- Hi Bruno
When you do your test using HWND_TOP (only) make sure you set an appropriate delay such as 5000ms and as soon as you click the button, focus another window in its place. On windows XP you will find with HWND_TOP the window will remain behind other windows.
I'm using Mate 1.6 desktop environment.