Kinda related, I'd just like to see the arrow keys in all the tree node views in MusicBee work the same way as Windows Explorer and most other programs.
They're mostly okay, but Left arrow should collapse the current node if it is expanded, or take you to the parent node if it is not. Currently it just moves up the list, which can be time consuming if you're at the bottom of a long list of folders.
Could also duplicate OP's request with a modifier key.
e.g.
Ctrl+Right Arrow could expand all child nodes.
Bee excellent to each other...