1st of all thank you for developing such a feature rich application.
Im not sure if it is right place to share feedback, but I'm redirected here from Google Play, so here is my feedback:
1) You have removed seek bar from library lists. Please add this. It is necessary while going through huge lists quickly.
2) Also in list when multi select box is closed, the selected tracks are getting unselected. They must remain selected until they are unselected. It is not possible to play track by tapping when multi select options box is visible. Or you can add functionality to select, seek and play tracks while the box is visible. E.g. if user tapps track cover image the track should be selected/unselected, if user tapps track title it should be played, if user swipes left-right on a track it should be seek.
I am still going through the various new features.