Created attachment 144216 [details]
What happens when hovering, I did not used the mouse scroll wheel or arrow keys.

SUMMARY
When changing both kate and kwrite theme through the settings window, it seems that there's an invisible item under "Automatic Selection", that ends up at the bottom of the combobox list when scrolled past, causing the list to scroll down whenever the cursor hovers it.


STEPS TO REPRODUCE
1. Go to Tools > Configure Editor... > Color Themes
2. Click on "Default theme for [kate/kwrite]" Combobox
3. Scroll Past "Automatic Selection" and the empty item under it
4. Hover at the end of the combobox list, a few px tall

OBSERVED RESULT
The list scrolls automatically

EXPECTED RESULT
The list should scroll only when activated

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Arch
(available in About System)
KDE Plasma Version: 5.23.4
KDE Frameworks Version: 5.88.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
Attached small mkv as illustration.