@Override
public void onEvent(Event event) {
gridLabelTypes.renderAll();
final Rows rows = gridLabelTypes.getRows();
for (Iterator i = rows.getChildren().iterator(); i.hasNext();) {
final Row row = (Row) i.next();
final LabelType labelType = (LabelType) row.getValue();
Hbox hbox = (Hbox) row.getChildren().get(2);
Button btnDelete = (Button) hbox.getChildren().get(1);
if (!canRemoveLabelType(labelType)) {