OK.
2 probables bugs (maybe already reported. Sorry if they are):
- rating a track doesn't update the Album Rating ("store ratings in the music file" unticked, "auto-calculate album rating" ticked). Sometimes Pressing F5 works, but usually, have to restart MB.
- dunno if it's intended, but we can't expand the right sidebar in Now Playing tab (Theater Mode). Only the header appears (think this one was already reported, not sure)