namespace "shadow" doesn't work as expected

<zk>
    <vlayout xmlns:sh="shadow"   apply="org.zkoss.bind.BindComposer">
        <sh:apply template="desktop" />

        <sh:template name="desktop">
            in namespace
        </sh:template>
    </vlayout>
    <vlayout   apply="org.zkoss.bind.BindComposer">
        <apply template="desktop" />

        <template name="desktop">
            without namespace
        </template>
    </vlayout>
</zk>

without namespace

in namespace
without namespace