extjs tabpannel无法显示激活tab数据
        this.fp = new Ext.form.FormPanel({
            fieldWidth:80,
            labelAlign:'right',
            border:false,
            items:{
                xtype:'tabpanel',
                id:'piddd',
                activeTab:0,
                deferredRender:false,
                border:false,
                height:350,
                items:[{
                    title:'分配类别',
                    items:{
                        layout:'fit',
                        border:false,
                        items:this.gridRole
                    }
                }]  
            }
        });

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向上面的代码， activeTab:0,激活第一个tab，gridRole能正常取到数据。但是无法显示出来。如果将上面的代码改成

        this.fp = new Ext.form.FormPanel({
            fieldWidth:80,
            labelAlign:'right',
            border:false,
            items:{
                xtype:'tabpanel',
                id:'piddd',
                activeTab:0,
                deferredRender:false,
                border:false,
                height:350,
                items:[{},{
                 &nbs