I saw this in the morning and was looking forward to try this out all day, but only got home now & have MusicBee infront of me now, yay.
Folder collapse/expand all works, even with multiple nested folders (i.e. /name/name/playlistA.m3u). Thanks for that!
Parent-folder content 'aggregation' (that it shows' all child playlists combined contents) seeems to work through multiple nested folders too. Just waiting for it to finish 'compiling' some of the larger ones (where/how is this stored btw ?)
There seems to be one small issue with nested folders though, but unsure what was off here & I can't reproduce it...:
When accessing a nested folder I did get MB to error and to get stuck / only displaying a single message continuously, saying:
"Unable to access: C:\Programs\MediaPlayers\MusicBee\Library\Playlists\RadioArchive\2008\.xautopf"
This was not an issue if I 'unparented' it from the nested folder, also, if I created a new folder and chucked all its' playlists in the new folder, the error was gone (no write-protection on the folder with the issue though...), and re-parenting the recreated folder with the same playlist did not show the same issue.
I added one large playlist for testing, holding 50k songs in in a 5mb .m3u file, which takes the parent folder to take a long time to show the aggregate (10 minutes in now and still nothing so far - as is I have no idea if it is stuck / errored / is still processing - the only way to tell [=that it hasn't finished] was to click between folders, the previously processed ones would display [=change view to the contents of the child-playlists combined content] whereas the currently being processed one would then show the previous' selections contents.
Would be great again to have some sort of (optional & continuous) error/console/'what is MB doing' read-out.
ps. it now finished, about 15 minutes in, but refresh is laggy now - i.e. if I click the folder that holds the contents of the huge playlist, the track-list refresh/rerender takes about 2-3 seconds. I'll test around with this some more.