https://bugs.winehq.org/show_bug.cgi?id=57456
--- Comment #8 from daniel daniel.penalized@proton.me --- I've been testing for the past few hours and have some additional information, I hope it's useful!
Firstly, there is a workaround for this issue in labwc/wlroots, which is: take the window out of fullscreen, toggle the window's maximized state, and then put the window back in fullscreen. In labwc/openbox terms: ToggleFullscreen > ToggleMaximize > ToggleFullscreen. This workaround worked in the four games I tested: Splinter Cell 1, Splinter Cell 2, SWAT 4 and SWAT 4: The Stetchkov Syndicate (SWAT 4 expansion), with some issues:
In Splinter Cell 2, at first the game does not fill in to your monitor's resolution, you need to press a key or make some movement with the cursor to fill it (yeah, I couldn't find an effective way to apply this workaround). Even when the game fills to your monitor's resolution, it becomes completely frozen, making it impossible to play.
In SWAT 4 and SWAT 4: The Stetchkov Syndicate, in both games the cursor doubles, showing the system and game cursor, which is easily fixed by pressing any key on your keyboard. Otherwise, in SWAT 4 this workaround works perfectly, however, in SWAT 4: The Stetchkov Syndicate, the window resets completely when entering any loading screen, which makes you need to redo the workaround at those times.
Secondly, besides this issue (the lack of window centering and a black background), I believe that the resolution scaling is also not working. I mean, even when I apply this workaround, the games internal resolution doesn't seem to change, so the game remains at a lower resolution. This is easily visible in Splinter Cell 1, with this workaround, the graphics are visibly lower compared to the graphics when I change the game's resolution in the settings. This could be another issue, which probably needs to be opened as a bug report, but neither of these two issues happen with this MR: https://gitlab.winehq.org/wine/wine/-/merge_requests/5057, which makes me assume that the two things are correlated.
I have logs of some tests. I was even going to attach them, but it seems that Bugzilla does not support sending multiple files in a single comment, so I decided to omit them.