* @see com.vaadin.data.Container.Viewer#setContainerDataSource(Container)
*/
@Override
public void setContainerDataSource(Container newDataSource) {
if (newDataSource == null) {
newDataSource = new HierarchicalContainer();
}
// Assure that the data source is ordered by making unordered
// containers ordered by wrapping them
if (Container.Hierarchical.class.isAssignableFrom(newDataSource