Extjs面板嵌套，items下的panel不显示？？？
var panel=new Ext.Panel({ 
               titile:"面板的标题", 
               width:400,//面板的高度
               html:"<h1>面板的主题内容</h1>"
            });

new Ext.Viewport({ 
       layout:"border", 
       items:[{
         region:"center", 
         collapsible: true,
         html: '<iframe scrolling="auto" frameborder="0" width="100%" height="100%" src="stuinfo/grjbxx.jsp" ></iframe>' ,
         title:"个人基本信息"
       },{
         region:"south", 
         collapsible: true,   
         xtype:'panel',      
         height:200, 
         layout:'fit',
         title:"底部面板",
         items : panel  //这个panel不显示
       }] 
}); 
------解决方案--------------------
var panel=new Ext.Panel({ 
               title:"面板的标题", 
               width:400,//面板的高度
               html:"<h1>面板的主题内容</h1>"
            });