The option to double click on a song can either open a new playlist or append the current one, this is problematic if you dont want the clutter of endless useless one song playlists but still want to preserve the playlists you starred. Could you add an append unless saved playlist option so we can have it create a new playlist if all the playlists currently up is saved, but append to the first one that isnt saved.
Currently the only options seem to be to wipe out playlists you want when you click on a song in a desktop folder or to have it open a new playlist every time. Or to append songs to a playlist you want to preserve. Rather it would be nice to have options to keep playlists you select to be preserved, preserved.