SUMMARY Would be nice to have this effect for Activities. For example I don't use Virtual Desktops only Activities. SOFTWARE/OS VERSIONS Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.24 KDE Frameworks Version: 5.90 Qt Version: 5.15.2 ADDITIONAL INFORMATION
*** This bug has been marked as a duplicate of bug 449919 ***
BTW. Here https://bugs.kde.org/show_bug.cgi?id=444456 I got very well explanation (with video examples), and learned that actually drag and drop is possible for Activities, only with some limitations.