Ext.tree.TreeNode 树型菜单不能显示

//定义并构造西部面板
var westRegion = {
    region:'west',
    id:'west-panel',
    iconCls: 'tabs',
    title:'报表',
    split:true,
    width: 200,
    minSize: 175,
    maxSize: 400,
    collapsible: true,
    margins:'0 0 0 5',
    layout:'accordion',
    layoutConfig:{
        animate:true
    },
    //items: [manageTree,msgTree]
listeners : {
"beforerender" : function(){
    function addNode(node,obj){
var childNode = new Ext.tree.TreeNode({
id : obj.id,
text : obj.text,
leaf : obj.children?false:true,
listeners : {
"click" : obj.children?Ext.emptyFn : openReport
}
});
node.appendChild(childNode);
if(obj.children){
for(var i=0;i<obj.children.length;i++){
addNode(childNode,obj.children[i]);
}
}
};

var treeThis = this;

    Ext.Ajax.request({
    url:'getTreeAll.action',
    params:{},
    success:function(resp){
//     alert(resp.responseText);
    treeNodes = Ext.util.JSON.decode(resp.responseText);
    for(var i=0;i<treeNodes.length;i++){
    var tp = new Ext.tree.TreePanel({
    title : treeNodes[i].text,
    autoScroll: true,
    animate: false,
    containerScroll: true,
    rootVisible: false,
    autoHeight : true,
    border : false
    });
    var root = new Ext.tree.TreeNode({
    id: treeNodes[i].id,
    text: treeNodes[i].text,
    expandable:true,
    expanded:true,
    leaf: false
    });
    for(var j=0;j<treeNodes[i].children.length;j++){
    addNode(root,treeNodes[i].children[j]);
    }
    tp.setRootNode(root);
    treeThis.add(tp);
//     treeThis.render();
    }
//     alert(treeNodes.length);
    }

    });


}
}
};
var treeNodes;

情况如下图片