There are two ways to delete playlists: from the playlist menu, if you're deleting just one playlist, and via the Actions menu, if you need to delete more than one playlist at a time.
Deleting one playlist
If you want to delete just the one playlist, choose 'Delete playlist' from the playlist menu.
This will open up a confirmation pop up, where you have two options: to delete All Versions or just the Latest Version.
DISCO playlists have versions. Every time you make a change to a playlist and save it, it creates a new version.
What does deleting 'All Versions' mean?
Deleting all versions of the playlist completely removes the playlist from your DISCO. This can't be undone.
What does deleting the 'Latest Version' mean?
Deleting the latest version will just delete the most recent saved version of the playlist. After you delete the latest version, the playlist will revert to the version of the playlist saved before the most recent version. Think of deleting the latest version as a quick way to revert to an earlier saved version of the playlist if you save a change you'd like to undo.
Deleting multiple playlists
If you'd like to delete multiple playlists, select the playlists using multiple select and then choose Delete from DISCO from the Actions menu:
You'll then get a confirmation message asking you if you're sure you want to delete the playlists:
Does deleting playlists also delete the tracks from the DISCO?
No. Deleting a playlist only deletes the playlist; the tracks themselves remain in the DISCO.