+ /*
+ For the substitution of a single property, we tack the result onto
+ mutable_property_alist_ ; mutable_property_alist_ is empty after
+ Grob::Grob (Grob const&), except that System has all-elements set,
+ as a side product of typeset_grob () on newly copied spanners.
+
+ Here we clear that list explicitly to free some memory and
+ counter some of the confusion I encountered while debugging
+ another problem
+
+ (hwn 4/2/04)
+ */
+ if (sym == ly_symbol2scm ("all-elements"))
+ sc->mutable_property_alist_
+ = scm_assq_remove_x (sc->mutable_property_alist_,
+ ly_symbol2scm ("all-elements"));
+