Hello,
After recent Mutter update (ZorinOS 18), Vulkan/DXVK games open across both monitors simultaneously instead of a single display. This occurs when the game is set to Borderless Windowed mode.
This behavior started after the Mutter update to 46.2-1ubuntu0.24.04.12. The issue affects Vulkan/DXVK games, and appears to be a Wayland compositor regression related to multi-monitor handling.
Steps to Reproduce:
Use a system with two monitors:
Primary: 144 Hz
Secondary: 60 Hz
Launch Steam
Start a game (e.g. Path of Exile)
Expected Result:
The game should open on one selected monitor only, respecting the primary display or in-game monitor selection.
Actual Result:
The game window spans both monitors at the same time, effectively stretching the image across displays. Enabling fullscreen mode and switching back to borderless fixes the issue, until another game restart.
Frequency:
Always (100% reproducible), issue was not present on 46.2-1ubuntu0.24.04.10
Additional findings:
Setting: gsettings set org.gnome.mutter experimental-features "['scale-monitor-framebuffer']"
fixes the first launch only
Restarting the game reproduces the bug
Logging out/in resets behavior
Matching both monitors to 60 Hz does NOT fix the issue
Found this in journalctl:
Window manager warning: Buggy client sent a _NET_ACTIVE_WINDOW message with a timestamp of 0
Window manager warning: Window 0x4e00003 sets an MWM hint indicating it isn't resizable,
but sets min size 1 x 1 and max size 2147483647 x 2147483647
Does anyone else have this bug or knows a fix?