_ardour_buttons_box.pack_end (delete_button, false, false);
_ardour_buttons_box.pack_end (save_button, false, false);
_ardour_buttons_box.pack_end (add_button, false, false);
_ardour_buttons_box.pack_end (delete_button, false, false);
_ardour_buttons_box.pack_end (save_button, false, false);
_ardour_buttons_box.pack_end (add_button, false, false);