Just found a bug regarding play next and when filtering the media library.
I did this:
1. Filter the media library with an artist
2. Play a song
3. Change filter so that the currently playing song is not visible, but you have a bunch of other songs
4. Right click and play next on any song except the first in the list
5. Wait till the playing song ends or press next
6. It will now start playing the first song in the list, not the one you picked as play next.
7. If you press next again, it will now go to the song you picked as play next
