Trying to start a GTK4 application (like baobab) under KDE/Plasma, I get
$ baobab
(baobab:61840): Gtk-WARNING **: 15:51:32.115: Unknown key gtk-modules in /home/michael/.config/gtk-4.0/settings.ini
Segmentation fault (core dumped)
$ cat /home/michael/.config/gtk-4.0/settings.ini
[Settings]
gtk-application-prefer-dark-theme=false
gtk-cursor-theme-name=breeze_cursors
gtk-cursor-theme-size=24
gtk-decoration-layout=icon:minimize,maximize,close
gtk-enable-animations=true
gtk-font-name=Noto Sans, 10
gtk-icon-theme-name=breeze
gtk-modules=colorreload-gtk-module
gtk-primary-button-warps-slider=false
gtk-xft-dpi=147456
$ dpkg -L kde-config-gtk-style | grep colorreload
/usr/lib/x86_64-linux-gnu/gtk-3.0/modules/libcolorreload-gtk-module.so
It appears this module is only available for GTK3, but added for GTK4,
causing any GTK4 app to segfault (thus the RC severity).
~/.config/gtk-4.0/settings.ini appears to be autogenerated by KDE/Plasma.
I did not manually change this file.
Regards,
Michael