Here is the thing:
A filter using focus: artist/main performer “Deutsche Kammerphilharmonie Bremen”.
Bookmark created.
But in my library is also another album where the DKB is the main performer:
I checked why that album (Iiro Rantala & DKB) does not appear in the focus/bookmark.
The metadata seems to be OK, nevertheless I added DKB as a main artist a second time:
Now this all looks OK, but the album dioes not appear in the bookmark.
WHY? 
I can’t immediately see what’s wrong here. Maybe you have two different entries for Deutsche Kammerphilharmonie Bremen? This happened to me a few times.
You can check under your artists.
There’s just one artis entry in the database:
In the album, the DKB and the soloist Iiro Rantala are separate entries so everything should work…
Quite interestingly, the soloist appears in the database (rightly so), …
BUT the filter does not work. It looks strange 
So if I cannot rely on the filters / focus, the whole thing with bookmarks does not make much sense.
And: when I use the top/right search function (not focus) and type “deutsche kammer…” the in “my albums” all albums appear (correct), including the one that does not appear in focus. I’m confused
Is the Kammerphilharmonie credited as a performer in the metadata of the Gershwin album? Who are credited on this album?
A focus doesn’t look at album artists but at performers.
Addition:
I added the album to my library. First it only had the Kammerphilharmonie as a primary artist, which seems to be the same as album artist.
Focussing on the Kammerphilharmonie didn’t yield any results.
Then I edited the album credits, and added the role of performer to the Kammerphilharmonie. Then it did show up in the focus.
The conclusion here is: a focus on performers does not look at album artists, which is quite odd, I must say. You would expect otherwise.
Hi Arlen. Thank you so much for your help. I now know about the roles in credits.
I would hope that it was just a metadata issue.
But I fully agree, focus should indeed look for the primary artist. How can I push this to roon?
Well, I don’t know if they did this deliberately. To me, it sounds very strange that an album artist/primary artist isn’t seen as a performer. I can’t imagine a use case for which it makes sense to exclude them, but perhaps Roon has a good argument for this.
But it is might also be just a bug.
Maybe @support knows the answer?
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.
