title: PrimeFaces CommandButton does not Update
body: <p>I'm trieng to update a gridPanel by pressing a Button(the Pie/Bar chart should not be shown):</p>
  
  <pre><code>&lt;h:form&gt;
      &lt;div class="ui-grid ui-grid-responsive"&gt;
          &lt;div class="ui-grid-row"&gt;
              &lt;div class="ui-grid-col-4"&gt;
                  &lt;p:panelGrid columns="1" layout="grid"
                      styleClass="ui-panelgrid-blank"&gt;
                      ...
                      &lt;p:panelGrid columns="2" layout="grid" id="buttons"
                          styleClass="ui-panelgrid-blank"&gt;
                          &lt;p:commandButton update="@form"
                              actionListener="#{buttonView.pieChart}" icon="ui-icon-disk"
                              title="Zeige Pie an" /&gt;
                          &lt;p:commandButton update="@form"
                              actionListener="#{buttonView.barChart}" icon="ui-icon-disk"
                              title="Zeige Bar an" /&gt;
                      &lt;/p:panelGrid&gt;
                  &lt;/p:panelGrid&gt;
              &lt;/div&gt;
              &lt;div class="ui-grid-col-8"&gt;
                  &lt;p&gt;...&lt;/p&gt;
                  &lt;p:panelGrid columns="1" layout="grid"
                      styleClass="ui-panelgrid-blank" id="charts"&gt;
                      &lt;p:chart id="pie" type="pie" model="#{userBean.model}"
                          responsive="true" /&gt;
                      &lt;p:chart id="bar" type="bar" model="#{chartView.barModel}"
                          style="height:300px" responsive="true" /&gt;
                  &lt;/p:panelGrid&gt;
              &lt;/div&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/h:form&gt;
  </code></pre>
  
  <p></p>
  
  <p>My code somehow does not seem to work.</p>