final PAttachedPopupPanel levelPopupPanel = new PAttachedPopupPanel(true, fieldContainer);
final PPopupPanel popupWidget = levelPopupPanel;
popupWidget.setWidget(popupContent);
popupWidget.show();
popupWidget.addCloseHandler(new PCloseHandler() {
@Override
public void onClose(final PCloseEvent closeEvent) {
updateMainFormField();
}