Hi, thank you! This topic helps a lot. I’m using Kubuntu 25.10 (KDE)
As stated in the Updating Unreal Engine on Linux to SDL3 | Unreal Engine 5.7 Documentation | Epic Developer Community SDL3 does not work well with Wayland yet.
While Wayland support is compiled into the SDL3 library, Unreal Editor using pure Wayland is unusable. Mouse click events are not correctly received (though touch events are) and in general there are a number of issues. X11Wayland support is fine and Editor works as normal in that mode, but if you set
SDL_VIDEODRIVER=waylandand run using a Wayland window manager, Unreal Editor is not functional. Support for game targets using Wayland mode is also still untested.
Therefore**SDL_VIDEODRIVER=x11** is a must. Otherwise, all pop-ups or notifications will open in the center of the screen. This happens because Wayland uses relative positioning, while X11 uses absolute positioning.
example usage:
Terminal: export SDL_VIDEODRIVER=x11 && "/foo/bar/ue_5.7/Engine/Binaries/Linux/UnrealEditor"
.desktop: Exec=env SDL_VIDEO_DRIVER=x11 “foo/bar/ue_5.7/Engine/Binaries/Linux/UnrealEditor”
If you encounter DPI issues, try the -nohighdpi param. You can also try forcing resolution with -windowed -ResX=3840 -ResY=2160 (your resolution) or adjusting the Editor Scale in the settings.
Fixing double click:
The reason behind the double-click issue is that each tooltip is considered a new “window.”(?) . In the Content Browser, pop-ups open above the main window and steal focus, same for dropdowns or notifications.
Setting the global Window activation policy to "Focus under mouse" solves this, but you lose standard [ALT] + [TAB] functionality and encounter other unwanted behaviors.
A better solution is to set a Custom Window Rule in KDE that fixes almost all issues:
Window class: UnrealEditor
Window types: deselected: Normal window
Focus stealing prevention: Force/Extreme
Focus protection: Force/None
Accept focus: Force/No
With these setup, i rerely face any issues. In PIE mouse remains locked in the PIE window without leaving.
Additional Linux tips:
If you have vulkan sync issues, add -VulkanNoSync
If crashing due to mem alloc issues, try -ansimalloc