button.setStyleName("add-contact-btn");
button.addListener(new Button.ClickListener() {
@Override
public void buttonClick(Button.ClickEvent event) {
if (null == newContactWindow) {
NewContactPresenter presenter = injector.getBean(NewContactPresenter.class);
newContactWindow = new Window("Add New Contact", injector.getBean(NewContactView.class));
newContactWindow.setModal(true);
newContactWindow.setHeight("200px");
newContactWindow.setWidth("220px");
}