+MAKE_SCHEME_CALLBACK (Side_position_interface, calc_cross_staff, 1)
+SCM
+Side_position_interface::calc_cross_staff (SCM smob)
+{
+ Grob *me = unsmob_grob (smob);
+ extract_grob_set (me, "side-support-elements", elts);
+
+ for (vsize i = 0; i < elts.size (); i++)
+ if (to_boolean (elts[i]->get_property ("cross-staff")))
+ return SCM_BOOL_T;
+
+ Grob *common = common_refpoint_of_array (elts, me->get_parent (Y_AXIS), Y_AXIS);
+ return scm_from_bool (common != me->get_parent (Y_AXIS));
+}
+