Two Artist Albums

[simoncn]

This tag editor uses a semicolon as the separator to specify multiple values, so you need to set Artist to:

JJ Cale; Eric Clapton

and Artist Sort to:

Cale, JJ; Clapton, Eric

The semicolon is not part of the tag value in the file. It is the user-visible representation that your tag editor uses to show multiple values.

This doesn't work for AlbumArtist (with MinimServer) because MinimServer doesn't allow multiple values for AlbumArtist.