Use 'album artist' tag instead of 'performer'
Created by: mikelpr
otherwise this happens with properly tagged files from musicbrainz makes a huge mess in the sidebar
even if I hadn't tagged them with musicbrainz, this would still happen as I have many DJ sets where the artist tag is used for the true artist and the album artist tag is used for the mixer
my suggestion for files which don't have an album artist tag should fallback to artist then, as the performer tag is used for detailed information (well, at least on musicbrainz. still the artist tag is better supported most of the time)