Hello!
I would like to suggest the following for the side panel:
It would be lovely, if you could have 2 or more items among each other.
For example, "saved playlists" and among "automatic generation of playlists".
I use those 2 very often and help myself out with the "bookmark" feature. But that's suboptimal because many mouse clicks are involved.
Well, just a suggestion, maybe someone else finds this useful too.