In the left panel, when you double-click on a playlist or the library in the
left panel, RB must not stop playing (and especially if the played song is in
the selected playlist).

For example, if I'm listenning to a song, when I click on a playlist is most of
the time because I want that the next songs are from the selected playlist. If I
want to change the song, I will click "next".

At the moment there's no way to tell Rhytmbox "continue playing this but then
choose songs from the given playlist".

This bug is also particulary annoying when you are using the play queue because
it will skip the current played song in the queue and then playing the next song
in the queue (even if it is not in the playlist). It's a non-intuitive and
annoying behaviour (I never want to stop playing if I don't hit "stop").

Other information:
The strangest thing about this is if the current song is in the selected playlist.

Say that you are in the library and you are playing song A. You double click on
playlist "Rock" (A is in the "rock" playlist).

Music will be stopped. If you hit play, song A will be played from the beginning !