http://bugs.winehq.org/show_bug.cgi?id=33235
--- Comment #2 from Martin Štrympl sfence.software@gmail.com 2013-03-18 12:04:11 CDT --- Hmm. Yeah. It looks like a reason for this problem. But it isn't exmlain, why it works diffrent in native MS Window XP instalation in my Virtual Box and in wine on my Mac OS X system.
May be HWND_MESSAGE window in MS Window XP do automaticaly resend message to new parent. And not in wine. I have no idea.
May be it is some bug in my MS Window XP instalation that it receive WM_NOTIFY from both window correctly. Can you check it on some other window instalation? If it really work diffrent it is really wine bug, I think.
I was looking for solution of this problem etc. two days and I didn't find it (mean http://support.microsoft.com/kb/104069). If it is my fault and not wine fault, I am sorry for losing your time.