Operating system
Linux
tags: flatpak, kde, plasma, wayland, css, kubuntu
Joplin version
Joplin 3.5.12 (prod, linux), flatpak
Desktop version info
Operating System: Kubuntu 25.10
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.2
Kernel Version: 6.17.0-5-generic (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 3600 6-Core Processor
Memory: 64 GiB of RAM (60.7 GiB usable)
Graphics Processor: AMD Radeon RX 6600 XT
What issue do you have?
Hi everyone,
I wanted to share a solution for a specific problem I encountered with Joplin (Flatpak) on KDE Plasma (Kubuntu).
Problem:
My custom CSS (userchrome.css and userstyle.css) was being ignored by the app, even though the files were in the correct directory and the app had permissions to read them. The UI kept following the system's dark theme/colors instead of the CSS instructions (e.g., forced white background).
Solution:
The issue was the GPU Acceleration. It seems that on KDE, GPU rendering can override internal CSS color styles in Electron apps.
How to fix it:
Open Flatseal.
Select Joplin.
Scroll down to the Device section.
Deactivate GPU acceleration (device=dri).
Restart Joplin.
After disabling this, the app switched to software rendering, and all my custom CSS rules (like #ffffff !important) were applied correctly.
Hope this helps anyone struggling with the same setup!