code: private void addChildren(final UIClassification _uiClass,
                               final boolean _force)
      {
          if (_force || _uiClass.isExpanded()) {
              getModelObject().add(_uiClass);
              for (final UIClassification child : _uiClass.getChildren()) {
                  addChildren(child, _force);
              }
          }
      }
docs: Recursive method to add child classifications.
  
  @param _uiClass  classification to add
  @param _force    force expanded