[Wayland] `--autofit-larger=100%x100%` makes mpv unusable

mpv Information

mpv v0.41.0-388-g1301fdb2e Copyright © 2000-2026 mpv/MPlayer/mplayer2 projects
 built on Apr  7 2026 19:09:48
libplacebo version: v7.362.0 (v7.360.0-8-g4c654e50)
FFmpeg version: N-123859-ge7696357de
FFmpeg library versions:
   libavcodec      62.29.101
   libavdevice     62.4.100
   libavfilter     11.15.101
   libavformat     62.13.102
   libavutil       60.29.100
   libswresample   6.4.100
   libswscale      9.7.100

Other Information

- Linux version: Arch btw.
- Kernel Version: Yes
- GPU Model: Intel
- Mesa/GPU Driver Version: 26.0.4
- Window Manager and Version: KDE Plasma 6.6.4
- Source of mpv: Yes
- Latest known working version: Unknown.
- Issue started after the following happened: Nothing ever happens.

Reproduction Steps

1. Open big video av://lavfi:testsrc=size=4000x6000 with --autofit-larger=100%x100%

Expected Behavior

OSC is not behind taskbar. Autofit should fit window into working area of the screen.

Actual Behavior

OSC, at least default one is behind taskbar, making mpv unusable. It is also not possible to resize window because of #17712. Which makes mpv unusable.

Note that KDE prevents moving top window border above the screen area, which makes it more severe.

Log File

No.

Sample Files

Yes.

I carefully read all instruction and confirm that I did the following:

• I tested and confirmed that the issue exists with the latest release version or newer.
• I provided all required information including system and mpv version.
• I produced the log file with the exact same set of files, parameters, and conditions used in "Reproduction Steps", with the addition of --log-file=output.txt.
• I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• I attached the full, untruncated log file.
• I attached the backtrace in the case of a crash.

Reproduce the issue with av://lavfi:testsrc=size=4000x6000 and --autofit-larger=100%x100% under Wayland. Investigate the window sizing and working-area behavior, with #17712 as related context; done means the OSC is not behind the taskbar and the window can be resized normally.