Interesting thing to test I think is to verify if current cross-built winecfg shows the same issue on Windows, before changing them all.
Well, I already added a testcase to show this behavior, but it can't hurt, I guess.
I needed to remove the link to "wine_get_unix_file_name" in theme.c, and remove the manifest from the exe, then it starts up on windows. For some reason, it started itself a few hundred times, but then the GUI showed up.
The issue is the same on windows, the combobox doesn't work properly the way it currently is, with the patch I submitted it works fine. Actually, windows does show a listbox without the patch, but it's merely 2 pixels in height.
Regards, Fabian Maurer