https://bugs.winehq.org/show_bug.cgi?id=53066
--- Comment #19 from Zhiyi Zhang zzhang@codeweavers.com --- (In reply to Roman Pišl from comment #18)
I also use a custom Qt application with no other bugs observable which spams console with "OpenThemeData() failed for theme 16 (WINDOW). (Element not found.)". That is probably for another bug report..
Could you provide this application?
The problem with Qt5 applications is that they are querying a lot of Vista+ theme properties. However, Wine's Light theme originally only uses XP theme properties so a lot of the properties needed are not present and applications end up using the wrong parts or states. So I have to add support for all these Vista+ theme properties to get Qt5 applications working properly, which will take quite some time.