Preventing natural signs from being printed when the key signature changes
When the key signature changes, natural signs are automatically printed
to cancel any accidentals from previous key signatures. This may be
prevented by setting the printKeyCancellation property to
#f in the Staff context.
\relative c' { \key d \major a4 b cis d \key g \minor a4 bes c d \set Staff.printKeyCancellation = ##f \key d \major a4 b cis d \key g \minor a4 bes c d }