title: Button not rendered after upload file
body: <p>I want to render a button after upload a file, I have <code>selectOneMenu</code>to chose options, when I upload the file with the first option, the button didn't rendered but it rendered after I chose the second option.</p>
  
  <p>ManagedBean.java</p>
  
  <pre><code>private boolean viewImport;    
  public boolean isViewImport() {
      return viewImport;
  }
  
  public void setViewImport(boolean viewImport) {
      this.viewImport = viewImport;
  }
  
  public void processFiless(FileUploadEvent event) {      
  setViewImport(true); 
  }
  </code></pre>
  
  <p>import.xhtml</p>
  
  <pre><code>    &lt;ui:composition template="./../../../../template.xhtml"&gt;
      &lt;ui:define name="content"&gt;
              &lt;h:form id="form1" prependId="false"&gt;
                  &lt;p:growl id="messages"/&gt;
                  &lt;h1&gt;&lt;h:outputText value="#{customerData.importBatchTitle}" /&gt;&lt;/h1&gt;
                  &lt;div class="formSection"&gt;
                      &lt;p:panel  header="#{app['import.fileSelectionForm']}" id="importFile" toggleable="true" toggleSpeed="300"&gt;
                          &lt;h:graphicImage styleClass="formimg" url="/images/orange/fleche2.gif"/&gt;&lt;h:outputText value="#{app['import.contract.parameter.primal']}" /&gt;
                          &lt;h:selectOneMenu value="#{customerData.parameterType}"&gt;
                              &lt;f:selectItems value="#{customerData.parameterTypeItems}" /&gt;
                              &lt;p:ajax actionListener="#{customerData.selectionParameterType}" event="change" update="form1"/&gt;
                          &lt;/h:selectOneMenu&gt;
                          &lt;br/&gt;
                          &lt;br/&gt;
                          &lt;h:panelGroup rendered="#{customerData.viewUpload}"&gt;
                              &lt;p:fileUpload update="form1" fileUploadListener="#{customerData.processFiless}" &gt; 
  
                                  &lt;p:ajaxStatus&gt;
                                      &lt;f:facet name="start"&gt;
                                          &lt;h:graphicImage value="/images/ajaxloading.gif" /&gt;
                                      &lt;/f:facet&gt;
                                      &lt;f:facet name="complete" &gt;
                                          &lt;h:outputText value="" /&gt;
                                      &lt;/f:facet&gt;
                                  &lt;/p:ajaxStatus&gt;
                              &lt;/p:fileUpload&gt;
                          &lt;/h:panelGroup&gt;
                      &lt;/p:panel&gt;
                      &lt;br/&gt;
                       &lt;f:subview id="modifyCustt"  rendered="#{customerData.viewImport}"&gt;
                       &lt;p:commandButton value="ok"&gt;&lt;/p:commandButton&gt;
                       &lt;/f:subview&gt;
                    &lt;/div&gt;
              &lt;/h:form&gt;
          &lt;/ui:define&gt;
      &lt;/ui:composition&gt;
  </code></pre>