Why do the staves double up when I change to certain polyphonic staff styles in one project, but if I copy the music over to another, the staves don't double up. For example, I want to use the piano 1+2/3+4 staff style. In my original project this will give me two trebles and two bass clefs, which is not what I want. When I do the same thing in a new project then it stays at one treble and bass cleff, which is what I want to use.