src/main/java/org/efaps/ui/wicket/components/classification/ClassificationTree.java
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);
            }
        }
    }
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);
            }
        }
    }
Recursive method to add child classifications.

@param _uiClass  classification to add
@param _force    force expanded