title: adding errors to FacesContext.getCurrentInstance().addMessage shows message but doesn't prevent from processing
body: <p>I'm validating data selected in a dropdown - <code>ice:selectOneMenu</code> on a form. On the valueChangeListener. I have validation which adds an error message: </p>
  
  <pre class="lang-java prettyprint-override"><code>FacesContext.getCurrentInstance().addMessage(fieldId, 
      new FacesMessage(FacesMessage.SEVERITY_ERROR, msg, msg));
  </code></pre>
  
  <p>The validation works on the Bean and the error message is displayed to the user but when the "Save" commandbutton is clicked, the page continues the confirm page when it's suppose to stay on the capture page until the correct value is selected in the dropdown. </p>
  
  <p>Why does the page continue to confirm the page?   </p>