http://bugs.winehq.org/show_bug.cgi?id=14640
--- Comment #14 from Roderick Colenbrander thunderbird2k@gmx.net 2009-01-19 14:13:44 --- The problem is not limited to just this option but to most of the pfd options. I don't think windows is rewriting the format to RGBA but it likely just ignores this flag altogether. There are several problems. First of all the behavior of ChoosePixelFormat is not well defined and second parts of it are implemented in the icd of a vendor :( Because the behavior isn't well defined we don't know what microsoft is doing on the pixel format table. We have had similar issues with other options.
In order to fix this bug (and all the others) we need to know exactly what Microsoft is doing :( Else I fear that we only make the issue a lot worse as right now our ChoosePixelFormat seems to work for most apps (it has been in a much worse state).
Roderick