- Remove all tracks from the library (or at least all tracks for an artist)
- Run maintain Database with the options Rebuild FTS index, Optimize database and rebuild database
- The deleted artists should now be gone from the list in Music > Artists and when opening the column browser in Music > All tracks, but all subnodes under the Music > Artists node will still be there
I just figured out that this issue is not related to the deletion of tracks at all. Subnodes under Music > Artists just don't properly refresh, regardless if tracks are deleted or tracks with new artists are added. Forcing a reload with Running window.doReload() fixes the issue.