https://bugs.winehq.org/show_bug.cgi?id=2082
--- Comment #164 from Aaron Paden aaronbpaden@gmail.com --- Correct me if I'm wrong, but my understanding of the issue is that it can't be implemented correctly because ddraw allows you to draw arbitrarily on the screen, something that doesn't make sense on modern composited environments.
IIRC from what I've read in the past, old display servers were implemented as a single framebuffer, and applications had access to a small portion of that framebuffer (that's why we have an Expose event in X11).
Nowadays, applications draw on their own framebuffer. Even if the wine devs tried to implement this "correctly", it would be impossible on composited desktops or in Wayland.
However, is there any reason this can't be implemented correctly for virtual desktops, at least for older Windows versions?
Actually, I think the virtual desktop windows aren't as decoupled from the underlying display server as I'd hope. Fullscreen applications still make xrandr calls, for example, and I've noticed bugs where applications can escape the virtual desktop.