I work with a few sax players on occasion, and I have to insist that they NEVER play the melody when I'm singing. It's a useless, redundancy that really chokes my style. It seems like a natural thing to do, if you're a melody instrument, but the important thing to remember is the comfort of the "lead" voice....whatever it is. Vocals always take priority in a case like this, so if the singer likes to be shadowed ...... so be it. Just don't try it behind me. Grrrrr....