I just tried it on MC22.0.75 on Debian. Dragging playlists does not work on this platform. I think this is a more general issue though, because you can't drag songs in Playing Now either. I've previously been told that this drag and drop functionality is difficult to do, but that it's on the long term list for Linux MC functionality.
I would really like to see drag and drop for playlists, songs, etc work, as it seems rather basic. I'm not arguing that it's not hard to do. I'm sure it is. I'm just saying that, as a user facing feature, it's something almost everyone expects.
Thanks,
Brian.