That’s intended - the left shows the relationships, the right shows the works (once). It might not be the most intuitive though, given some comments on this thread.
I think that’s intentional either because that’s not always a 1:1 replacement for the instrument/vocals (for example, you’ll sometimes see opera singers listed as “soprano vocals [Role]: Artist”, where replacing “soprano vocals” with “Role” would probably not be an improvement - same for “violin [1st]: Artist”)
Them being grey is meant to show they can’t be selected, but maybe it can be made a bit more visible while still being clear. I added a ticket for that (MBS-12866)