http://bugs.winehq.org/show_bug.cgi?id=18571
--- Comment #5 from Roderick Colenbrander thunderbird2k@gmail.com 2009-06-11 16:08:55 --- The issue has been fixed (there were 2 bugs) but it wasn't clear whether the bugs were in Wine or not. In the first case VisualWorks emulates menu windows and it used ShowWindow with the flag SW_RESTORE for all types of windows. This didn't look correct, so we changed it to pass SW_NOACTIVATE (which is what is done in wine for standard win32 windows) and now the menu window is unmanaged as it should be.
The second issue is a bug in the smalltalk vm for sure. It recycles window handles for the menu and it then uses SetWindowPos but it doesn't pass SWP_NOACTIVATE, so again the menu window became managed and the app lost focus.
Since this is a very tricky area of win32/winex11.drv I can't say whether it were just app bugs or that there also bugs in Wine.