listbox issues with invalidatePartial

<zk>
    <zscript>
        ListModelList model = new ListModelList(Arrays.asList(new String[] {"A", "B", "C"}));
    </zscript>
    <custom-attributes org.zkoss.zul.listbox.rod="false"/>
    <listbox id="lb" model="${model}" >
        <listhead>
            <listheader label="col1"/>
        </listhead>
    </listbox>
    <button label="hide" onClick="lb.setVisible(false);"/>
    <button label="show" onClick="lb.setVisible(true);"/>
    <separator/>
    <button label="show + replace model"
            onClick='lb.setVisible(true); model.clear(); model.add("replaced");'/>
    <button label="show + clear model"
            onClick='lb.setVisible(true); model.clear();'/>
    <button label="show + invalidatePartial"
            onClick='lb.setVisible(true); lb.invalidatePartial("rows");'/>
    <separator/>
    <button label="workaround (call invalidate)"
            onClick='lb.setVisible(true); model.clear(); lb.invalidate();'/>
</zk>