refer to attached file, tested on ZK 6.0.1

If apply "children" to a root component. AbstractRenderer.java cannot resoloveTemplate correct, because comp.getParent() = null

this will work
<zk>
<div>
<listbox children="xxx">...</listbox>
</div>
</zk>

this will throw exception, refer to attached file
<zk>
<listbox children="xxx">...</listbox>
</zk>