[GraemeJ]

Reason; currently when I create new setlist, I add songs that I haven't done for a while, and I can't remember if I have attached an mp3 audio to the file or not, so I have to right click to and edit audio to find out. 

Although I agree it might be a useful addition, you can already tell if there is a music file associated with any particular chart by the presence of the tied note symbol on the right of the line. Personally, I compile a setlist first, then check if there are any audio files missing (on the assumption that I need one, not always the case).