https://bugs.winehq.org/show_bug.cgi?id=37876
--- Comment #8 from Dmitry Timoshkov dmitry@baikal.ru --- (In reply to Anastasius Focht from comment #7)
I generated a full relay log. The log is very large hence I only provide the part when the top-level window and all child windows get created and later shown.
Thanks Anastasius. According to my tests under Windows7 it's really WS_EX_COMPOSITED that makes the window behave just like a normal one regarding ShowWindow/WS_VISIBLE/SetWindowPos(SWP_SHOWWINDOW). Without that style set the window can't be made visible using these methods.