commandButton不会触发操作

Question

<h:form id="main_form"> 

    <p:treeTable var="catalog" value="#{catalogSelectBean.root}" lazy="true" selection="#{myView.selectedCatalogNode}" selectionMode="single">
    <p:column>
                                <f:facet name="header">
                                    <h:outputText value="Name" />
                                </f:facet>
                                <h:outputText value="#{catalog.name}" />
                            </p:column>

  <p:column width="100">
    <f:facet name="header">
      <h:outputText value="Desc"/>
    </f:facet>
    <h:outputText value="#{catalog.description}"/>
  </p:column>

</p:treeTable>

<!-- The problem commandButton below-->


<p:commandButton  action="#{myView.updateProductListForSelectedCatalog}"
                                    update=":main_form:selectProductTable" value="Bring products">

</p:commandButton>

<!-- The problem commandButton above-->



     <p:dataTable id="selectProductTable" var="product"  value="#{myView.productDataModel}" paginator="true"  selection="#{myView.selectedProduct}" >

        <f:facet name="header">
            Product Selection
        </f:facet>

        <p:column selectionMode="single" />
            <p:column headerText="name">
                <h:outputText value="#{product.name}" />
    </p:column> 

    </p:dataTable>

    <p:commandButton action="#{myView.setSelectedProductToForm}"
                    update="main_form"
                    value="Set">
    </p:commandButton>



</h:form>   

如果我在selectproducttable中选择了某些东西，那么问题commandButton不会触发操作。