Choral score with Piano staves

I have a choral score with a piano instrument with treble and bass clefs. The choral staves are complete, and now I'm trying to enter the piano accompaniment. When I try to input notes in either the piano stave's treble or bass clefs, it automatically creates the same note two octaves apart in the opposite clef. If I delete a note from one clef, it deletes the note in the other clef. How do I input notes into the piano staves independently on the treble and bass clefs? Is there a setting I'm missing?