Created attachment 141296 [details]
Three screenshots showing what I mean

SUMMARY
This requires a very specific set of steps to reproduce, specially now that Overview is in development and it is where it is most visible.

First, if a panel is set as "Windows Can Cover", the "Show Desktop" call hides it as if it were just any other window. One of the ways of hiding it is just by entering Plasma's Edit Mode or by pressing the Show Desktop icon. Similarly, the new Overview identifies the panel as a window and lists it on the Overview as such. While I know that the issue with Overview could be result of being still in development and in no way in a release candidate state, the part of hiding the panel set as "Windows Can Cover" when in the Show Desktop call, is a little of an odd behavior. Now it could possibly happen with other visibility options but I only tested with this one.

Still on the Overview topic, it would be interesting if the docks/panels stayed where they are when on overview instead of disappearing, kinda like how it happens on Deepin 20 and Gnome 40

STEPS TO REPRODUCE
1. Just set a panel or dock with the behavior "Windows Can Cover"
2. Enter Plasma's Edit Mode or press the Show Desktop button on the panel

OBSERVED RESULT
Panel/dock is hidden as if it were a regular window

EXPECTED RESULT
Panel/dock stay on screen

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20210902
KDE Plasma Version: 5.22.80
KDE Frameworks Version: 5.86.0
Qt Version: 5.15.2
Kernel Version: 5.13.13-1-default (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i3-7020U CPU @ 2.30GHz
Memory: 11.5 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 620