This zul file below produces inconsistent results across browsers. IE and FF only show Menu 1 but Chrome shows Menu 2 as well.

<zk>
<hlayout>
<window title="Menu 1">
<tree>
<treechildren>
<treeitem>
<treerow>
<treecell>test</treecell>
</treerow>
</treeitem>
</treechildren>
</tree>
</window>
<window title="Menu 2">
<tree>
<treechildren>
<treeitem>
<treerow>
<treecell>test</treecell>
</treerow>
</treeitem>
</treechildren>
</tree>
</window>
</hlayout>
</zk>