Extjs4.2中treeview定义插件bufferedreader看不到效果

[blood2323]

在store设置了100条数据，但是看不到效果，是还要配置什么参数吗，求大神帮忙
数据读取都是正常的，就是bufferedreader这个插件没有效果

这是view部分

Ext.define('MDM.view.DeviceOperate.DeviceOperate_tree', {
    extend:'Ext.tree.Panel',
    requires:[
        'Ext.tree.*',
        'Ext.data.*'
    ],
    alias:'widget.deviceoperatetree',
    xtype:'tree-reorder',
    store:'DeviceOperateTree_Store',
    rootVisible:false,
    useArrows:true,
	border:0,
	bodyCls:'tree-body',
	cls:'org',
	enableDD:false,
	loadMask: true,
	animate: false,
	plugins: [{
			ptype: 'bufferedrenderer'
		}],
    initComponent:function () {

        var store = this.store;

        Ext.apply(this, {
            store:store,
            listeners:{
                'itemclick':function (obj, record, item, index, e, eOpts) {
                    console.log(record.data.name);
                }
            }
        });
        this.callParent();
    },
    onExpandAllClick:function () {
        var me = this,
            toolbar = me.down('toolbar');

        me.getEl().mask('Expanding tree...');
        toolbar.disable();

        this.expandAll(function () {
            me.getEl().unmask();
            toolbar.enable();
        });
    },

    onCollapseAllClick:function () {
        var toolbar = this.down('toolbar');

        toolbar.disable();
        this.collapseAll(function () {
            toolbar.enable();
        });
    }

});

这是store部分

Ext.define("MDM.store.DeviceOperateTree_Store", {
    extend:'Ext.data.TreeStore',
    model:'MDM.model.DeviceOperateTree_Model',
    proxy:{

        type:'ajax',
        url:'/justsy/department/search/tree',
	//	url:'data/test.json',
        reader : {
            type:'json',
            root:'content'
        }
    },
    pageSize:100,
    autoLoad:true

})