Ok, did a minimal fix, you can test it at the usual place : http://raine.1emulation.com/archive/tux/raine.7z
This forced me to reinstall the dev tools in windows, which showed me that the compilation of the 32 bits version was broken in mingw32, so nobody did that clearly ! Actually I had never reinstalled these after upgrading my windows disk which is now a ssd about 1 year ago or so.
Anyway the fix is at 2 levels, it forces the desktop size to the video mode size instead of looking at the usable area, but except that I got a stupid game screen in the lower left part of the screen when I was in fullscreen, only for the 64 bits version, so it forced me to make the binary in mingw32 and not in linux as usual, there is clearly some dll problem, probably specific to windows 10/11 somewhere.
So this archive is bigger, it includes a new libcrypto-3.dll which was not required before.
Also since the bug is saved in the config file, the fix can work only if raine is not started in fullscreen with a broken config file, if it's the case you need to return to some windowed mode and switch again to fullscreen, or delete your config file.
It seems to work for me, I guess I'll have to make something more official after that mess...
Problem is that it probably breaks compatibility with old windows version for good this time. It's not my fault, it's the way windows is made, they willingly make things harder and harder to stay compatible with old versions.
edit : and uploaded a new dlls64-0.96.7z with an updated SDL2.dll, 0.28 was becoming quite old. This should still be compatible with all 0.96 versions, and the libcrypto-3.dll is only in this raine.7z package for now.