Problema com JSF e commands immediate

<f:view>
    <h:form>
	 <h:inputText binding="#{testeMb.txtTeste}" size="40" disabled="true">
         </h:inputText>
         <h:commandButton actionListener="#{testeMb.esconder}" value="Testar" id="testar" immediate="true">
         </h:commandButton>
         <h:commandButton value="Esconder" actionListener="#{testeMb.esconder}" immediate="true">
         </h:commandButton>
          <h:panelGroup binding="#{testeMb.panel}" rendered="false">
        	<h:dataTable border="1" value="#{testeMb.lista}" var="nome">
	        	<h:column id="column1">
					<h:commandLink actionListener="#{testeMb.testar}" immediate="true">
						<h:outputText value="#{nome}"></h:outputText>
					</h:commandLink>
					<f:facet name="header">
						<h:outputText value="Coluna"></h:outputText>
					</f:facet>
				</h:column>
			</h:dataTable>
		</h:panelGroup>
	</h:form>
</f:view>

public class MB_Teste
{
	private HtmlInputText txtTeste;
	
	private HtmlPanelGroup panel;
	
	private DataModel lista = new ListDataModel();

	public HtmlInputText getTxtTeste()
	{
		return txtTeste;
	}

	public void setTxtTeste(HtmlInputText txtTeste)
	{
		this.txtTeste = txtTeste;
	}
	
	public void testar(ActionEvent event)
	{
		String nome = lista.getRowData().toString();
		txtTeste.setValue(nome);
		
		FacesContext.getCurrentInstance().renderResponse();
	}
	
	public void esconder(ActionEvent event)
	{
		if(event.getComponent().getId().equals("testar"))
			panel.setRendered(true);
		
		else
			panel.setRendered(false);
		
		FacesContext.getCurrentInstance().renderResponse();
	}

	public HtmlPanelGroup getPanel()
	{
		return panel;
	}

	public void setPanel(HtmlPanelGroup panel)
	{
		this.panel = panel;
	}

	public DataModel getLista()
	{
		List<String> lista = new ArrayList<String>();
		lista.add("Teste 1");
		lista.add("Teste 2");
		
		this.lista.setWrappedData(lista);
		
		return this.lista;
	}

	public void setLista(DataModel lista)
	{
		this.lista = lista;
	}
}