What to do if FacesMessage is set but not displayed

Event: The message is not displayed even though FacesMessage is set as the content.

Execute the method with ajax

  <h:form id="formId">
    <div id="uploadArea">
<!--...abridgement...-->
          <f:ajax event="change" execute="uploadArea" render="uploadArea" listener="#{uploadBean.uploadFile}" />
<!--...abridgement...-->
      <div>
        <h:message for="uploadArea" errorClass="error" warnClass="warn" infoClass="info" />
      </div>
    </div>
  </h:form>

I set a message as content in a method, but it doesn't appear

    public void uploadFile(AjaxBehaviorEvent event) throws IOException {
        if (!isUpload()) {
            FacesMessage message = new FacesMessage(FacesMessage.SEVERITY_INFO, "", "The file was not selected.");
            event.getFacesContext().addMessage("uploadArea", message);
//...abridgement...

Output HTML

<form id="formId" name="formId" method="post" action="/tryJsf/base.jsf" enctype="application/x-www-form-urlencoded">
  <input type="hidden" name="formId" value="formId">
  <div id="uploadArea">
<!--...abridgement...-->
    <input id="formId:file" type="text" name="formId:file" style="display:none;" onchange="mojarra.ab(this,event,'change','uploadArea','uploadArea')">
    <div>
    </div>
  </div>
  <input type="hidden" name="javax.faces.ViewState" id="j_id1:javax.faces.ViewState:0" value="-7689768516583343150:2206148480801750608" autocomplete="off">
</form>

Cause: Unknown (Please tell me.)

Apparently it didn't reappear after the f: ajax method was executed. render =" uploadArea " ... was ignored? Is HTML tag useless? Shouldn't it be a JSF tag? Isn't a component not written with JSF tags?

The clientIds of components that will participate in the "render" portion of the Request Processing Lifecycle. ajax(JSF 2.2 View Declaration Language: Facelets Variant)

Workaround: Change the div tag to h: panelGroup

Execute the method with ajax

  <h:form id="formId">
    <h:panelGroup id="uploadArea">
<!--...abridgement...Since I made it a JSF tag, make it an id attribute to specify..-->
          <f:ajax event="change" execute="formId:uploadArea" render="formId:uploadArea" listener="#{uploadBean.uploadFile}" />
<!--...abridgement...-->
      <div>
        <h:message for="formId:uploadArea" errorClass="error" warnClass="warn" infoClass="info" />
      </div>
    </div>
  </h:form>

It was displayed when I set the message as content in the method

    public void uploadFile(AjaxBehaviorEvent event) throws IOException {
//...abridgement...Same as before correspondence...Change only the specified id attribute...
            event.getFacesContext().addMessage("formId:uploadArea", message);
//...abridgement...Same as before correspondence...