After invoking Overview, I can drag windows around even from one monitor to another. But in fact it does not happen.
STEPS TO REPRODUCE
1. Launch Plasma on a system with 2 or more monitors. Press Meta + W
2. Try to move window while in Overview from one screen to another
3. Release mouse button.
Nothing happens, window moves back.
I'd expect windows would be transferable from one screen to another.
(available in About System)
KDE Plasma Version: 5.24.0
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2
It should be either not allowed to drag windows on another screen while in Overview, or (better) implemented this way - that's cool.
*** This bug has been marked as a duplicate of bug 448566 ***