With picom enabled, some GTK3 apps lose their borders #58
Description
With picom enabled, some GTK3 apps lose their borders. The shadow rendered by picom remains active, but it will be offset by the width of the border that has gone missing. See screenshot, the upper window works as it should (Xfce4 Application Finder), the lower shows the issue (Thunar):
Other applications with this issue include:
- Xfce4 Terminal
- Mate Terminal
- Terminator
The issue was identified to be a window manager issue rather than an issue in picom here: yshui/picom#285
Some fixes made in other window managers are linked there as well.
I tried adjusting the picom settings (different rendering backends, no shadow etc.), as well as adjusting the border color in WPrefs, and none of those could fix the issue.
The issue can be reproduced on many distros, I tried Debian 13 Trixie, Xubuntu 25.04, Linux Mint 22.1, and Fedora 42.