Listbox ROD will not render item in a correct position

Scroll to item99, it will jump to item 41

<zk>
<zscript>
Object[] o = new Object[200];
</zscript>
<listbox width="100px" height="100px">
<listitem forEach="${o}" label="item ${forEachStatus.index}" />
</listbox>
<grid width="100px" height="100px">
<rows>
<row forEach="${o}">
<label value="item ${forEachStatus.index}"/>
</row>
</rows>
</grid>
</zk>