I am trying to add swing playback to a vocal/piano piece for rehearsal with my elementary group (Rudolph the Red-Nosed Reindeer).  I have everything entered in and I am trying to set the playback to swing.  The vocal staff is swinging, but the piano staff is not.  I have tried to put the swing expression on both staves, but it will only attach to the vocal line.  I need the piano accompaniment playback to be swung as well when the tempo kick up to the actual "Rudolph" part.

Any suggestions as to why the express is only working on the vocal line and not the piano line?

Thank you,