+ /* each child's skyline was calculated according to the common refpoint of its
+ elements. Here we need all the skylines to be positioned with respect to
+ a single refpoint, so we need the common refpoint of the common refpoints
+ of the elements of the children */
+ vector<Grob*> child_refpoints;
+ for (vsize i = 0; i < elements->size (); i++)
+ {
+ extract_grob_set ((*elements)[i], "elements", child_elts);
+ Grob *child_common = common_refpoint_of_array (child_elts, (*elements)[i], other_axis (a));
+ child_refpoints.push_back (child_common);
+ }
+ Grob *common_refpoint = common_refpoint_of_array (child_refpoints, me, other_axis (a));
+