In the Big Piano Settings you can color the notes and yellow is out of scale but it doesn't apply over to the piano roll notes also, I think I requested this years ago but there is usually a ten year lag !
Also see here http://www.pgmusic.com/forums/ubbthreads.php?ubb=showflat&Number=418850

RapidComposer uses Blue=Scale note Green=Chord note and Red=Out or Passing note. The piano roll background color changes with the chord/scale in the chord track, you have customization of whatever colors you like.