@redstrate, I expect that @medin is referring to what the undermentioned examples depict:
which despite being apparently deliberate, considering that they’re modals provided by Kirigami, all have exactly the same issues, because that they’re not real windows — instead mere boxes.
I expect that those issues are why Microsoft abandoned such a design (for all except purely notification dialogues, for rationale unknown to me) in Windows 11.
Thanks, @dzon: 476996 – Allow window border to render on plasmashell windows too.