- elt_l_->set_extent_callback (Axis_group_interface::group_extent_callback,a1);
- elt_l_->set_extent_callback (Axis_group_interface::group_extent_callback,a2);
+ // if (!me->has_extent_callback_b (a1))
+ if (me->has_extent_callback_b (Score_element::molecule_extent, a1))
+ me->set_extent_callback (Axis_group_interface::group_extent_callback,a1);
+ if (me->has_extent_callback_b (Score_element::molecule_extent, a2))
+ me->set_extent_callback (Axis_group_interface::group_extent_callback,a2);