Created attachment 143816 [details] Outline of windows Currently, the top line of Kickoff is too visible and it looks like a visual glitch. The top outline of windows have a better level of opacity.
Created attachment 143817 [details] Outline of Kickoff
Oh noes, I forgot to add the wishlist importance again.
Yep, this is reasonable IMO.
The appearance was changed for Plasma 5.27 to remove this top line.