title: Ajax update/render does not work on a component which has rendered attribute
body: <p>I'm trying to ajax-update a conditionally rendered component.</p>
  
  <pre><code>&lt;h:form&gt;
      ...
      &lt;h:commandButton value="Login" action="#{login.submit}"&gt;
          &lt;f:ajax execute="@form" render=":text" /&gt;
      &lt;/h:commandButton&gt;
  &lt;/h:form&gt;
  &lt;h:outputText id="text" value="You're logged in!" rendered="#{not empty user}" /&gt;
  </code></pre>
  
  <p>However, that does not work. I can assure that <code>#{user}</code> is actually available. How is this caused and how can I solve it?</p>