Kubuntu 20.04 system settings add languages window maximized at 4K UHD quickly flashes

[Martin Bruzina]

Let's try with fresh install: Kubuntu 20.04.1 with default installer options + all packages updated, upgraded, systemsettings package version 4:5.18.4.1-0ubuntu1:

- Go to System Settings -> Regional Settings -> Language
- (I am not sure this step is necessary): add additional three languages (in my case cz, sk, ru)
- Maximize window at 4K UHD (3840x2160) display without any Plasma panel, the window occupies a whole area of the display
- Click the button Add languages...

Expected result:
- Add languages window shows languages list and after initial render stays static

Actual result:
- Add languages window flashes quickly, blinking indefinitely
- Just restore or resize the window to stop it

[Martin Bruzina (bruzina)]

The issue is NOT happening on Kubuntu 22.04.2.

I propose closing it, as it doesn't happen anymore.