@ann0see noticed UI glitches in the Qt6 preview builds in #2299 (comment)_

1. Strange lines:
   On Windows 11 there seem to be strange lines on the GUI which disappear on click. It looks as if one marked some invisible button:

2. Another issue
   

3. A macOS issue (I doubt it's new):
   
   The lines seem to be at the wrong position. On macOS I think Qt6 is an improvement (at least UI wise)