Here's the problem. As I've described above I've been putting in Brilliant Classics 170 CD "Complete Works of Mozart". (and yes, my wife and I celebrated the 250th anniversary with a fine bottle, and attempted to inspire two teenage daughters with the great man's music........OK , so you can't win them all!)

As previously described, I've split the set into ten virtual "box sets" of various sizes up to 23 CDs. Each disc has the Composer Field set to "Wolfgang Amadeus Mozart" and the Artist Field set to various artists via the tick box. Each CD in a particular volume has its Title field set to (for example) "Mozart (complete works) Volume 1: Symphonies", and The multi-disc Part Title fields set along the fines "Volume 1(CD5)......".

When I view the list of CDs in the "tree" Content window, Set to view "Entire Collection", all of the virtual box sets show up with their subsidiary CDs in the correct order. Perfect!

If I now change the view to "Composer", not all of the volumes show up under composer "Wolfgang Amadeus Mozart" and in some of the volumes that do, some of their subsidiary CDs are missing, and show up under [none] as single discs (even though the multi-disc "Part #" field set to(for example) "5/11".

So what's going wrong?