smaller_hbox->pack_start (_preset_combo, false, false);
smaller_hbox->pack_start (_preset_modified, false, false);
smaller_hbox->pack_start (add_button, false, false);
smaller_hbox->pack_start (_preset_combo, false, false);
smaller_hbox->pack_start (_preset_modified, false, false);
smaller_hbox->pack_start (add_button, false, false);