Force artist index values

[Knur]

Great, that worked : Artist.indexTag is now working as expected (I think).

I understand now how the displayTag indexTag are working, and what the renderer App is showing...
For instance, Lumin is showing the AlbumArtist as a subtext whenever an album list is displayed... Even though I have AlbumArtist:nil as you suggested !
But I can force that subtext to behave with a AlbumArtist.displayTag.

So, all is good (for now), thank you Simon !
(As for for tidying, I feel you, I'm working in IT...)