Masking allows you to cover up portions of a page and make them invisible to PlayScore 2. For example, if a song in a songbook ends half way down the page and you don’t want the beginning of the next song to play you can mask it off.
Another use for masking is to hide any part of a page that is preventing correct recognition. For example, some vocal scores begin with an indication of the voice part ranges. If this causes a playback problem just mask it off.