title: JSF ajax commandbutton not updating primefaces picklist
body: <p>This is the code:</p>
  
  <pre><code>&lt;h:form id="articleForm" &gt;
      &lt;p:commandButton value="Select tags" ajax="true" &gt;
          &lt;f:ajax execute="@form" render="@form :articleForm:tags" /&gt;
      &lt;/p:commandButton&gt;
  
      &lt;p:pickList id="tags" value="#{articleController.dualListModelForTags}" var="tag" itemLabel="#{tag.tag}" itemValue="#{tag}" converter="distinctTagConverter"&gt;
          &lt;f:facet name="sourceCaption"&gt;Distinct tags&lt;/f:facet&gt;  
          &lt;f:facet name="targetCaption"&gt;Connected tags&lt;/f:facet&gt;
      &lt;/p:pickList&gt;
  &lt;/h:form&gt;
  </code></pre>
  
  <p>When the commandbutton is clicked, the getDualListModelForTags() in the backing bean is called and executed. In getDualListModelForTags() I make some modifications so I want the picklist to be updated. But the picklist(id=tags) is not rendered again.  Only when I refresh the page, are the modifications made to the picklist.</p>