hi, when I try to add a vertical panel into a tab item I cant do that. For example

Code:
public void onModuleLoad() {
            final Button bGuardar = new Button("Guardar");

            final  TabPanel vista = new TabPanel();
            vista.setWidth(450);
            vista.setAutoHeight(true);

            final TabItem titulo = new TabItem("Alianzas");
            titulo.addStyleName("pad-text");
            titulo.setLayout(new FormLayout());

            titulo.add(bGuardar);

            vista.add(titulo);
 
            bGuardar.addSelectionListener(new SelectionListener<ComponentEvent>() {
             
       public void componentSelected(ComponentEvent ce) {
                        VerticalPanel vp = new VerticalPanel();
                        TextField tf= new TextField();
                         tf.setFieldLabel("test");
              TextField tf1= new TextField();
                         tf1.setFieldLabel("test1");
                         vp.add(tf);
                         vp.add(tf1);
                         titulo.add(vp);
               }
    });

             RootPanel.get().add(vista);

    }
As a result I only can see the button but when I click the button the vertical panel cant be added to my tab panel. Is possible add vertical panel to a tab item?

Thank you for your help.