ui/src/main/java/ucar/nc2/ui/event/ActionCoordinator.java
public void addActionSourceListener( ActionSourceListener l) {
    if (!eventType.equals(l.getEventTypeName()))
      throw new IllegalArgumentException("ActionCoordinator: tried to add ActionSourceListener for wrong kind of Action "+
         eventType+ " != "+ l.getEventTypeName());

    lm.addListener(l);
    l.addActionValueListener(this);
  }
public void addActionSourceListener( ActionSourceListener l) {
    if (!eventType.equals(l.getEventTypeName()))
      throw new IllegalArgumentException("ActionCoordinator: tried to add ActionSourceListener for wrong kind of Action "+
         eventType+ " != "+ l.getEventTypeName());

    lm.addListener(l);
    l.addActionValueListener(this);
  }
add an ActionSource listener