@Override
 public void initialize(IManagedForm form) {
   IFeatureModel model = (IFeatureModel) getPage().getModel();
   if (model != null) model.addModelChangedListener(this);
   super.initialize(form);
 }
 @Override
 public void dispose() {
   IFeatureModel model = (IFeatureModel) getPage().getModel();
   if (model != null) model.removeModelChangedListener(this);
   super.dispose();
 }