Hi,
I switched to MB 3.1 out of curiosity and found out a bag there: Manual Order (3.1 version of Playlist Order from older versions) is not behaving as it's supposed to be. I'd even say it's not working at all (clicking this option sorts tracks in very random order, manual moving of a track gives same effect - just a random order).
Unfortuantelly dwongrading to the lates 3.0 build (3.0.6249) didn't solve the problem and it still exist, causing managing playlists be completelly impossible.