Would want to report a bug (which I have been having for years without being able to track the culprit). There has been no updates since 2015 so it should be marked as not safe to use at the plugins page, unless it is fixed...
If there is a single panel with Playlist Organizer loaded and you close all playlists loaded within foobar, as soon as you try to create a new playlist in any way (File\new playlist, sending tracks to new playlist, etc.) foobar gets blocked indefinitely. The plugin clearly gets broken as soon as there is no playlist at some point. There is no crash (and no log that points to the culprit), it simply keeps processing indefinitely.
- Ensure there is at least one active playlist.
- Put Playlist Organizer in the layout OR open it in a new window (view/playlist organizer) and keep it opened.
- Close all playlists (ctrl + w). It will close active playlist, repeat until there is none.
- Try to create a new playlist via menus or double clicking on the library items, etc.
There is no way workaround to it unless the plugin is removed from a panel after restarting foobar and then creating a new playlist.
- Force foobar closing.
- Remove Playlist organized from layout. If it was loaded in its own window, then ensure it's closed.
- There is no active playlist and no playlist loaded at this point.
- Create a new playlist (now it should work).
- Playlist organizer can the be used as usual, but never close the last playlist.
Tested it with clean install, both with CUI and DUI layouts and no other variables.