sclass ConceptsComboBox<A extends Concept> extends JComboBox<A> {
  Concepts concepts;
  Class<A> conceptClass;
  AWTOnConceptChanges updater;

  *(Concepts *concepts, Class<A> *conceptClass) {
    updateItems();
    
    updater = new AWTOnConceptChanges(concepts, this, l0 updateItems);
    updater.install();
  }
  
  void updateItems {
    setComboBoxItems(this, freshList());
  }
  
  swappable Cl<A> freshList() {
    main list(concepts, conceptClass);
  }
}