public void dispose() {
   super.dispose();
   FeatureModelManager mng = PDECore.getDefault().getFeatureModelManager();
   mng.removeFeatureModelListener(this);
   fModel.removeModelChangedListener(this);
   if (fSiteLabelProvider != null) fSiteLabelProvider.dispose();
 }
 public void initialize() {
   refresh();
   FeatureModelManager mng = PDECore.getDefault().getFeatureModelManager();
   mng.addFeatureModelListener(this);
 }