concatenated Artist & Composer Tags

[m.ss.l]

on a related issue, it appears that when MS sends the AlbumAritst for Album lists, the formatting differs:

If there is an AlbumArtist, it uses AlbumArtist.displayFormat
If there is no AlbumArtist (just concatenated AlbumArtist), is uses Artist.displayFormat

ie if there is an AlbumArtist, & Artist.displayFormat={$artist^^: $composer^[^]}, it just shows the AlbumArtist Tag