Many gtk3 themes are no longer working correctly with the latest updates. This is the error output that is generated when trying to start a gtk3 application with the affected theme enabled: (gedit:2385): GLib-GObject-WARNING **: gtype.c:4204: type id `0' is invalid (gedit:2385): GLib-GObject-WARNING **: can't peek value table for type `<invalid>' which is not currently referenced Segmentation fault (core dumped) Some example themes are: Zukitwo, Mint-X
Hard to say what is going on, without at least a stacktrace here.
It seems to work again with the latest updates. Anyhow, thanks for taking care.