+The @code{\once} prefix may also be used in front of many
+predefined commands to limit their effect to one musical moment:
+
+@lilypond[quote,verbatim,relative=1]
+c4 d
+\once \stemDown
+e4 f |
+g4 a
+\once \hideNotes
+b c |
+@end lilypond
+
+However, predefined commands of the form @code{\...Neutral},
+@code{\...Off} and @code{\un...} use @code{\revert} internally rather
+than @code{\override} so prefixing these with @code{\once} has no
+effect.
+