fix skyline thinko

diff --git a/lily/axis-group-interface.cc b/lily/axis-group-interface.cc
index bd00b283073a0e9e09ca531887a1f870272cb0b5..3e9450c846139f977af064db4ba1f596ae15f01c 100644 (file)
--- a/lily/axis-group-interface.cc
+++ b/lily/axis-group-interface.cc
@@ -279,8 +279,10 @@ Axis_group_interface::combine_skylines (SCM smob)
   Grob *me = unsmob_grob (smob);
   extract_grob_set (me, "elements", elements);
   Grob *y_common = common_refpoint_of_array (elements, me, Y_AXIS);
+  Grob *x_common = common_refpoint_of_array (elements, me, X_AXIS);
 
-  assert (y_common == me);
+  if (y_common != me)
+    programming_error ("combining skylines that don't belong to me");
 
   Skyline_pair ret;
   for (vsize i = 0; i < elements.size (); i++)
@@ -291,6 +293,7 @@ Axis_group_interface::combine_skylines (SCM smob)
          Real offset = elements[i]->relative_coordinate (y_common, Y_AXIS);
          Skyline_pair other = *Skyline_pair::unsmob (skyline_scm);
          other.raise (offset);
+         other.shift (elements[i]->relative_coordinate (x_common, X_AXIS));
          ret.merge (other);
        }
     }