Tree vflex is broken without treecol

<?xml version="1.0" encoding="UTF-8"?>
<?page id="roletree_p"?>
<?component name="button" extends="button" style="border:none;background:white"?>
<zk>
<style src="/css/style.css"/>
<zscript><![CDATA[
int[] str = new int[100];
for(int i=0;i<100;i++){
str[i]=i;
}
]]>
</zscript>
<window id="win" title="角色信息" border="normal" height="100%">

<window height="5%" width="100%">
<button label="添加" src="/img/add.gif"/>
<button label="修改" src="/img/modify.gif"/>
<button label="?除" src="/img/del.gif"/>
</window>
<tree vflex="true" pageSize="100" width="90%" style="background-color:white;height:90%">
<treechildren>
<treeitem forEach="${str}" label="角色${each}" src="/img/role.gif"/>
</treechildren>
</tree>
</window>
</zk>

Refer to - http://sourceforge.net/forum/forum.php?thread_id=1848198&forum_id=510209

/Jumper