4 Staff margins are also markings attached to barlines. They should be
5 left of the staff, and be centered vertically wrt the staff. They may
6 be on normal staves, but also on compound staves, like the PianoStaff.
15 \notes \context PianoStaff <
16 \context Staff = treble {
17 \property PianoStaff.instrument = "Piano "
18 \property Staff.instrument = "Right " { c''4 }}
19 \context Staff = bass { \property Staff.instrument = "Left " \clef bass c4 }>