abstract sclass DynSCP extends DynModule {
  SingleComponentPanel scp;
  
  final JComponent visualize() { ret scp = singleComponentPanel(visualize2()); }
  void unvisualize2() { scp = null; }
  JComponent visualize2() { null; }
  
  void revisualize2() {
    lock lock;
    if (scp != null) scp.setComponent(visualize2());
  }
}