way to reproduce:
1) open xfmedia, so that you have playlist already loded
2) play a song
3) while song is playing, Start a new playlist
4) Add entry to playlist >> Directory
5) Add a directory
6) Old song is still playing, play a new song (doubleclick on song)
7) Press Next Track button
8) You'll start getting lots of
** (xfmedia:10083): CRITICAL **: xfmedia_playlist_shuffle_check: assertion
`plist->shuffle_bitmap && index < plist->shuffle_bitmap_len' failed
and xfmedia hangs.