this seems easy on the surface, but my first attempt at making this work flopped pretty hard. punting for now and opening a bug against it.

overview:
have SC send, in addition to track, artist, and album; track_id, artist_id, and album_id. when those are present, have the text label widgets on the NP screen have callbacks (by embedding the labels in a button widget) to bring up a context menu for that object.

this was kicked around early in the design phase and was decided not to be done because a) it was not particularly discoverable, and b) it's too easy to miss the item you want to hit and hit the one above or below it.

forum discussion suggests that this perhaps is still a good idea.