Currently, when adding a track to the currently playing playlist with shuffle on, we re-shuffle the entire playlist (with current track set as the first).
A better / more "expected" behavior would be
leave already played tracks as is in the order (up to and including cache.current shouldn't change)
leave "string of uninterrupted tracks that are in the play next stack" as is in the order
Currently, when adding a track to the currently playing playlist with shuffle on, we re-shuffle the entire playlist (with current track set as the first).
A better / more "expected" behavior would be