code: private void createAddContactSubForm() {
  		add(new WHeading(HeadingLevel.H3, "Add a new contact"));
  
  		WButton addBtn = new WButton("Add");
  		addBtn.setAction(new Action() {
  			@Override
  			public void execute(final ActionEvent event) {
  				addNewContact();
  			}
  		});
  		addBtn.setImage("/image/address-book-new.png");
  		newNameField.setDefaultSubmitButton(addBtn);
  
  		WContainer container = new WContainer();
  		container.add(newNameField);
  		container.add(addBtn);
  
  		WFieldLayout layout = new WFieldLayout();
  		add(layout);
  		layout.addField("New contact name", container);
  		add(new WAjaxControl(addBtn, new AjaxTarget[]{repeater, newNameField}));
  	}
docs: Create the UI artefacts for the "Add contact" sub form.