title: Primefaces dataTable is duplicated on page
body: <p>Have review(for adding review or comments) component in my application.<br>
  When add review, that <code>p:dataTable</code> is updated with ajax.</p>
  
  <p><strong><em>before adding review:</em></strong><br>
  <img src="https://i.stack.imgur.com/9aSrQ.png" alt="enter image description here"><br>
  <strong><em>after adding first review</em></strong><br>
  <img src="https://i.stack.imgur.com/GVy9L.png" alt="enter image description here"><br>
  <strong><em>refresh page(F5):</em></strong><br>
  <img src="https://i.stack.imgur.com/QXxJ7.png" alt="enter image description here"><br>
  <strong><em>after adding second review:</em></strong><br>
  <img src="https://i.stack.imgur.com/AJoEw.png" alt="enter image description here"></p>
  
  <p>jsf:</p>
  
  <pre><code>&lt;h:form onsubmit="return commValidator();"&gt;
   &lt;h:inputText value="#{comment.commentator}"/&gt;
   &lt;h:inputTextarea value="#{comment.body}";"/&gt;
   &lt;p:commandButton  value="send" action="#{showProducts.addComment}" update="comms"/&gt;
   &lt;p:dataTable id="comms" value="#{showProducts.comments}" var="com"&gt;   
    &lt;p:column&gt;#{com.commentator}(
     &lt;h:outputText value="#{com.postDate}"&gt;
     &lt;/h:outputText&gt;):
    &lt;/p:column&gt;
    &lt;p:column&gt;#{com.body}&lt;/p:column&gt;
   &lt;/p:dataTable&gt; 
  &lt;/h:form&gt;
  </code></pre>
  
  <p>The problem is <code>p:dataTable</code> component is displayed twice on page.<br>
  After new review been added, that newly created <code>p:dataTable</code> displayed.<br>
  How to make <code>p:dataTable</code> displayed already after go to page and once time?</p>
  
  <p>Thanks.</p>