title: Keep p:dialog open when a validation error occurs after submit
body: <p>Minimal example dialog:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;p:dialog header="Test Dialog"  
            widgetVar="testDialog"&gt; 
    &lt;h:form&gt; 
      &lt;p:inputText value="#{mbean.someValue}"/&gt; 
  
      &lt;p:commandButton value="Save" 
                       onsuccess="testDialog.hide()" 
                       actionListener="#{mbean.saveMethod}"/&gt; 
    &lt;/h:form&gt;       
  &lt;/p:dialog&gt; 
  </code></pre>
  
  <p>What I want to be able to do is have the mbean.saveMethod somehow prevent the dialog from closing if there was some problem and only output a message through growl.  This is a case where a validator won't help because there's no way to tell if someValue is valid until a save is submitted to a back end server.  Currently I do this using the visible attribute and point it to a boolean field in mbean.  That works but it makes the user interface slower because popping up or down the dialog requires hitting the server.</p>