Mouse wheel scrolling is not working if juCi++ gets focus directly after another window is closed

Whenever I close another window (a terminal window, for example) and juCi++ is then the next window to get focus, mouse wheel scrolling does not work. As far as I can tell, everything else works as normal. The wheel scrolling functionality is restored as soon as I switch to another window and then back to juCi++.

I'm on openSUSE Leap 15 with KDE Plasma at the moment if that narrows it down.

Let me know if you need any additional information or if I'm just doing it wrong. ;)