Still a problem in openSUSE-LEAP-15.2. This is very annoying! On the other hand, with Debian-11 beta (Bullseye) everything is fine. Tested with Debian packaged Geany and a Geany build I compiled myself. Both are GTK2 builds and I'm running a Plasma/KDE desktop with Klipper. So I guess this isn't an upstream bug. Please tell me if I can provide any more information to solve this bug!