JSF ajax命令按钮不更新primefaces选项列表

This is the code:

这是代码:

<h:form id="articleForm" >
    <p:commandButton value="Select tags" ajax="true" >
        <f:ajax execute="@form" render="@form :articleForm:tags" />
    </p:commandButton>

    <p:pickList id="tags" value="#{articleController.dualListModelForTags}" var="tag" itemLabel="#{tag.tag}" itemValue="#{tag}" converter="distinctTagConverter">
        <f:facet name="sourceCaption">Distinct tags</f:facet>  
        <f:facet name="targetCaption">Connected tags</f:facet>
    </p:pickList>
</h:form>
<h:form id="article