target_range_push.addSelectionListener(new SelectionListener() {
public void widgetDefaultSelected(SelectionEvent e) {
synchronized (synchro) {
synchronized (sync_tree) {
final Session session = synchro.getSessionFactory().getCurrentSession();
session.beginTransaction();
try {
addTargetAtCurrentPosition(new TargetIPv4Range("added by GUI",
GenericTools.stringToInet4Address(target_range_begin.getText()),
GenericTools.stringToInet4Address(target_range_end.getText())));
target_range_begin.setText("000.000.000.000");