I know this is a dead topic at this point, but I didn't know if I should create a new wishlist request when my idea is just a variation on this one. The image that CritterMan created to illustrate his idea is something I've been wanting for a long time, and given how many requests and complaints I've come across here over the years that would be solved by this feature, I can't believe this didn't gain more +1s at the time. What I would like to propose is a much simpler method for achieving the same result. Theoretically it should be far easier for Steven to implement, which hopefully means a better chance of him finding it worth the effort. Unfortunately, it will also mean far more effort for Musicbee users to take advantage of it, and so less likely for anyone to +1 the idea. Oh well.
My idea is this. Instead of basing the multiple expanded panels on album sets or release groups, a concept which is currently not supported in Musicbee so far as I know, perhaps it could be based solely on disc numbers. The previous ideas here would be far more elegant and user friendly, but I'm guessing they would also require a lot more time and effort for Steven to implement. In this case, albums with no disc numbers or tagged as disc one would not change. Tracks tagged as disc 2 would appear in the second expanded panel, tracks tagged as disc 3 would be in the third panel, etc. Obviously, this would have to be an optional feature, turned off by default.
Hopefully it wouldn't be too difficult to allow each panel to display different cover art, album titles, years, etc. I imagine the only way to realistically do that would be having tracks grouped to an album by folder in the Sorting/Grouping screen of Preferences and having all tracks you want grouped together in the same folder. If I'm right, then anyone who has different releases of the same album in separate folders, or the discs of a box set organized in sub folders, would have to completely reorganize their files. I know that would be a deal breaker for many people, but I for one think the result would be worth the many, many hours I would need to devote to making the necessary changes.
Anyway, assuming anyone even reads this post, I'm sure someone smarter than me will reveal the fatal flaw I've overlooked with this idea, but for now I can dream. If no one was interested in the far better ideas mentioned above, I know the chances of this one catching on are between slim and none, leaning heavily toward none, but I thought I would try. Thanks.