How to remove part names from the music

Hi,

I've been able to remove the part names from individual parts by selecting the entire staff and then erasing the names (and abbreviations) in the "Staff Setup" dialog.

However, when I try to do the same thing for the Piano staves, it doesn't work, and I can't figure out how to get rid of that text at the beginning of every line.

Any suggestions?

Thanks,
Andy