+MAKE_SCHEME_CALLBACK (Cluster, calc_cross_staff, 1);
+SCM
+Cluster::calc_cross_staff (SCM smob)
+{
+ Grob *me = unsmob<Grob> (smob);
+
+ extract_grob_set (me, "columns", cols);
+ Grob *commony = common_refpoint_of_array (cols, me, Y_AXIS);
+
+ return scm_from_bool (commony != me->get_parent (Y_AXIS));
+}
+