title: primefaces tabView activeIndex issue
body: <p>I have Primefaces TabView with two Tab like:</p>
  
  <pre><code>&lt;p:tabView dynamic="true" cache="false"
             onTabShow="scrollBottom(#{stanzaBean.activeIndex})"
             tabChangeListener="#{messaggioBean.onTabChange}"
             activeIndex="#{stanzaBean.activeIndex}" &gt;
  </code></pre>
  
  <p>it works fine, except that when I change the Tab the activeIndex isn't updated on the Server and it returns always the default value.
  I'm using primefaces 2.2.1.</p>
  
  <p>Thank you.</p>