Spanners cannot be tweaked after their creation. This includes both
@code{StaffSymbol} and @code{LedgerLineSpanner} which continue
-throughout the score (except if they are terminated by the
+throughout the score, except if they are terminated by the
@code{\stopStaff} command and then recreated using @code{\startStaff}
command.
@funindex \once
@funindex once
-@code{\override}, @code{\revert}. @code{\set}, and @code{\unset}
+@code{\override}, @code{\revert}, @code{\set}, and @code{\unset}
commands may be prefixed with @code{\once}. This causes such a
command to be effective only during the current musical
moment before the property reverts back to its previous value (this can