http://bugs.winehq.org/show_bug.cgi?id=33149
--- Comment #13 from Dmitry Timoshkov dmitry@baikal.ru 2013-03-18 00:28:17 CDT --- (In reply to comment #11)
Do you have Windows around to check with Spy++ or similar tool what styles MessageBox and splash windows have there?
As pretty much expected, under Windows both MessageBox and spash windows have WS_EX_TOPMOST style set.
Probably that's MessageBox code, who does that. There is even MB_TOPMOST style defined (which Wine doesn't support yet), but it appears that MB_TOPMOST is not passed to MessageBox by the application.