When I resize or close geany, I get drawing artifacts like these: https://youtu.be/ds-Opjl1N6c
I also get them on 3 other gtk3 based programs: termite, lxterminal, and emacs. I don't get them with baobab, wich also used gtk3, so maybe the issue is in the text drawing code?
[Here](https://github.com/thestinger/termite/issues/719) is another issue about the same thing.
A cursory search on https://gitlab.gnome.org/GNOME/gtk/-/issues didn't turn anything up, but maybe someone more familiar with the geanny codebase will have more success with a more targeted search.