Primefaces PanelMenu Target on iframe - jsf

Question

I use PanelMenu to build menu and the target is an iframe.
What I want to get, when I click menuItem in panelMenu, the result should display in iframe.
What I get, the result display in same windows, like "_self".
I tried use an other menu component, like slideMenu and tieredMenu, it display in target iframe, like what I want.
Is this a bug in panelMenu or may be I use in wrong way?
panelMenu code:
<h:form id="menuForm">
<p:panelMenu id="appSlideMenu" autoDisplay="false" toggleEvent="click" style="width:250px">
<p:submenu label="Homepage">
<p:menuitem value="Primefaces" url="http://www.primefaces.org" target="dcontainer" />
</p:submenu>
</p:panelMenu>
</h:form>
slideMenu code:
<h:form id="menuForm">
<p:slideMenu id="appSlideMenu" autoDisplay="false" toggleEvent="click" style="width:250px">
<p:submenu label="Homepage">
<p:menuitem value="Primefaces" url="http://www.primefaces.org" target="dcontainer" />
</p:submenu>
</p:slideMenu>
</h:form>
iframe code:
<h:body>
<div class="row-container">
<div class="first-row">
<div class="start-button">
<p:commandButton icon="fa fa-arrow-right" value="Start"
oncomplete="PF('nsidebar').show()" />
</div>
<div class="bottom">
<ui:include src="bottom.xhtml" />
</div>
</div>
<div class="second-row">
<iframe id="dcontainer" name="dcontainer"> </iframe>
</div>
</div>
<p:sidebar widgetVar="nsidebar" style="width:300px;">
<ui:include src="menu.xhtml" />
</p:sidebar>
</h:body>
Please help... Thank you...
Primeface 7.0 Community
Tomcat 9.0.6