private Image createaAddConnectiveImageButton(final RuleModeller modeller,
final SingleFieldConstraint constraint) {
Image addConnective = new ImageButton( images.addConnective() );
addConnective.setTitle( constants.AddMoreOptionsToThisFieldsValues() );
addConnective.addClickHandler( new ClickHandler() {
public void onClick(ClickEvent event) {
setModified( true );
constraint.addNewConnective();
modeller.refreshWidget();