protonscr

Steam sometimes starts up at the wrong size and with misaligned mouse coordinates until resized

steamopen Steam clientWindow managerDistro Family: Arch
ValveSoftware/steam-for-linux#12375 · opened 2025-10-12 by Reonu · updated 2026-03-14 · 3 comments · github
RReonu 2025-10-12 github

Your system information

  • Steam client version (build number or date): 1759533550
  • Distribution (e.g. Ubuntu): EndeavourOS with KDE Plasma
  • Opted into Steam client beta?: Yes, but it also happens on Stable
  • Have you checked for system updates?: Yes
  • Steam Logs: logs (1).tar.gz
  • GPU: Nvidia RTX 4070Ti Super

Please describe your issue in as much detail as possible:

Sometimes when Steam starts up it is at the wrong size/position and the mouse coordinates are misaligned (the mouse acts as if Steam was properly placed or sized). Grabbing the window from where the top of it should be to cause a resize event (since the window starts maximised) solves it for that session.

Image

Steps for reproducing this issue:

  1. Start Steam

In case it's relevant, I use a 2560x1440 resolution with 125% scaling. I also have a second monitor that runs at 1920x1080 with 100% scaling, but I use Steam on the main monitor.

RReonu 2025-10-12 github

I forgot to mention that I use Wayland (probably very relevant)

AASZ44 2025-11-04 github

Same issue here on Fedora Kinoite 42
Steam installed via rpm-ostree
GPU : RTX 3080
3440x1440 resolution with 125% scaling
Only one monitor

About:
Steam Beta Branch: Stable Client
Steam Version: 1759461205
Steam Client Build Date: Fri, Oct 3 04:27 UTC -08:00
Steam Web Build Date: Thu, Oct 2 20:12 UTC -08:00
Steam API Version: SteamClient023

rpm-ostree status
State: idle
Deployments:
● fedora:fedora/42/x86_64/kinoite
                  Version: 42.20251104.0 (2025-11-04T04:30:32Z)
...
RemovedBasePackages: fdk-aac-free 2.0.0-15.fc42
                           libavdevice-free libavfilter-free libavformat-free ffmpeg-free libpostproc-free libswresample-free libavutil-free libavcodec-free libswscale-free 7.1.2-1.fc42

LayeredPackages: akmod-nvidia akmods ffmpeg ffmpegthumbnailer gstreamer1-plugins-bad-free-extras gstreamer1-plugins-bad-freeworld
                           gstreamer1-plugins-ugly gstreamer1-vaapi libheif-freeworld libheif-tools libva-nvidia-driver libva-utils pipewire-codec-aptx
                           rpmdevtools rpmfusion-free-release rpmfusion-nonfree-release smb4k steam steam-devices xorg-x11-drv-nvidia xorg-x11-drv-nvidia-cuda

LocalPackages: akmods-keys-0.0.2-8.fc42.noarch
Nnickgerlock 2026-03-14 github

FWIW, I was seeing this issue on CachyOS (using KDE Plasma and Wayland), and I think I've found a fix (though I can't say for sure because the original bug seemed to happen intermittently).

Fix: add this environment variable for just the Steam App: QT_SCALE_FACTOR=1. For me, this fixed the issue, and interestingly the UI seems to be scaled exactly the same way as before. I think maybe the issue was caused by some kind of "double-scaling".

(BTW, at least in KDE Plasma, to add an environment variable for a single app, find the app using your launcher, right click, and select "Edit Application". The option for environment variables will be there)

Nothing extracted yet.