ListModel/TreeModel selection cannot share in two component

<zk>
    <zscript><![CDATA[
String[] data = new String[10];
for (int i = 0; i < data.length; i++)
	data[i] = "option " + i;


ListModelList model = new ListModelList(data);
    ]]></zscript>
    <listbox id="grid" model="${model}" onSelect="">
    	<listhead><listheader label="column" sort="auto"/></listhead>
    </listbox>
    
    <listbox id="grid2" model="${model}" onSelect="">
    	<listhead><listheader label="column" sort="auto"/></listhead>
    </listbox>
</zk>