Parece que não consigo disparar um evento quando estou dentro decolumn dodataTable. Aqui está minha demonstração simples

<h:form id="form">
    <!--This section of p:tree here seems to be the reason causing the event not fired when click the command button-->
    <p:tree value="#{viewBean.root}" var="node" dynamic="true" cache="false"  
                selectionMode="checkbox"  selection="#{treeBean.selectedNode}">  

        <p:ajax event="expand" update=":form:messages" listener="#{viewBean.onNodeExpand}" />  
        <p:ajax event="collapse" update=":form:messages" listener="#{viewBean.onNodeCollapse}" />  
        <p:ajax event="select" update=":form:messages" listener="#{viewBean.onNodeSelect}" />  
        <p:ajax event="unselect" update=":form:messages" listener="#{viewBean.onNodeUnselect}" />  

        <p:treeNode>  
            <h:outputText value="#{node}" />  
        </p:treeNode>  
    </p:tree>
    <h:panelGroup id="mygroup">
            <p:dataTable id="mytable" value="#{viewBean.foodList}" var="item">
                <p:column>
                    #{item}
                </p:column>
                <p:column>
                    <p:commandButton value="delete" 
                                     action="#{viewBean.delete}"
                                     update=":form:mygroup">
                        <f:setPropertyActionListener target="#{viewBean.selectedFood}"
                                                     value="#{item}"/>
                    </p:commandButton>
                </p:column>
            </p:dataTable>
    </h:panelGroup>
</h:form>

e aqui está meu bean gerenciado

@ManagedBean
@ViewScoped
public class ViewBean {

    private TreeNode root;  

    private TreeNode selectedNode;  
    private List<String> foodList;

    private String selectedFood;

    @PostConstruct
    public void init(){

        foodList = new ArrayList<String>();
        foodList.add("Pizza");
        foodList.add("Pasta");
        foodList.add("Hamburger");

        root = new DefaultTreeNode("Root", null);  
        TreeNode node0 = new DefaultTreeNode("Node 0", root);  
        TreeNode node1 = new DefaultTreeNode("Node 1", root);  
        TreeNode node2 = new DefaultTreeNode("Node 2", root);  

        TreeNode node00 = new DefaultTreeNode("Node 0.0", node0);  
        TreeNode node01 = new DefaultTreeNode("Node 0.1", node0);  

        TreeNode node10 = new DefaultTreeNode("Node 1.0", node1);  
        TreeNode node11 = new DefaultTreeNode("Node 1.1", node1);  

        TreeNode node000 = new DefaultTreeNode("Node 0.0.0", node00);  
        TreeNode node001 = new DefaultTreeNode("Node 0.0.1", node00);  
        TreeNode node010 = new DefaultTreeNode("Node 0.1.0", node01);  

        TreeNode node100 = new DefaultTreeNode("Node 1.0.0", node10);  
    }

    public void delete(){

        foodList.remove(selectedFood);

    }
    //setter and getter

    public void onNodeExpand(NodeExpandEvent event) {  
       FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_INFO, "Expanded", event.getTreeNode().toString());  

       FacesContext.getCurrentInstance().addMessage(null, message);  
    }  

    public void onNodeCollapse(NodeCollapseEvent event) {  
       FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_INFO, "Collapsed", event.getTreeNode().toString());  

       FacesContext.getCurrentInstance().addMessage(null, message);  
    }  

    public void onNodeSelect(NodeSelectEvent event) {  
       FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_INFO, "Selected", event.getTreeNode().toString());  

       FacesContext.getCurrentInstance().addMessage(null, message);  
    }  

    public void onNodeUnselect(NodeUnselectEvent event) {  
        FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_INFO, "Unselected", event.getTreeNode().toString());  

        FacesContext.getCurrentInstance().addMessage(null, message);  
    }  
}

Meu problema parece ser que o evento não foi disparado, o que significadelete nunca seja invocado.

Eu olhei em volta e sei que o Mojarra tem muitos problemas com componentes UIData aninhados, então tentei o Mojarra 2.1.4, ainda não resolvi o problema. Eu tentei o Myfaces 2.1.5, ainda não funciona !!! Isso é um erro do Primefaces? Eu até usoh:panelGroup como um invólucro paraupdate mas ainda não funciona.

EDITA: Acontece que op:tree acima dedataTable é a causa raiz do evento não disparada ao clicar nocommandButton. Se eu remover op:tree então funciona imediatamente. Observe que op:tree próprio @ funciona muito bem, ao clicar no check-out, evento disparado no meu bean gerenciad