Following ZUL Page does not render the menu correctly aligned:

<zk xmlns="http://www.zkoss.org/2005/zul">
<hlayout>
<label value="Actions:"/>
<menubar zclass="none">
<menu label="More">
<menupopup>
<menuitem label="Action 1"/>
<menuitem label="Action 2"/>
</menupopup>
</menu>
</menubar>
</hlayout>
</zk>

Please note that menubar has zclass="none"! If zclass is not set it renders correctly.
The problem happens on Firefox, Chrome and IE.
I use ZK 6.5.1. The same zul page above renders correctly with ZK 6.0.2.1.