p->item_p_->add_offset_callback (Side_position_interface::aligned_on_self, X_AXIS);
p->item_p_->add_offset_callback (Side_position_interface::centered_on_parent, X_AXIS);
announce_element (Score_element_info (p->item_p_,
p->item_p_->add_offset_callback (Side_position_interface::aligned_on_self, X_AXIS);
p->item_p_->add_offset_callback (Side_position_interface::centered_on_parent, X_AXIS);
announce_element (Score_element_info (p->item_p_,