Kdenlive opens multiple .exe copies.
Even after all kdenlive.exe files have been shut down via Task Manager, no actions (like moving Kdenlive files) are allowed by Kdenlive. "Action can't be performed, still open."
The only way to reset this is to shut down and restart computer.
NOTE: not sure if this is the right venue, but when I tried to post elsewhere as "Ask a Question" I was directed to a section exclusively devoted to apps; this question is not related to any apps.

old question.. for windows there is a work around to kill all instances...
viewtopic.php?f=265&t=142662