var corp_no = new Ext.ux.ComboBoxTree({
resizable:true,
renderTo : Ext.getBody(),
anchor:'95%',
tree : {
xtype:'treepanel',
loader: new Ext.tree.TreeLoader({
dataUrl:'org.do?subTranCode=tree'
}),
root : new Ext.tree.AsyncTreeNode({
id:'0',draggable:false,text:'机构树'
})
},
emptyText:'',
selectNodeModel:'exceptRoot',
name:'t004_sel',
hiddenName:'t004_sel',
fieldLabel: '单位',
listeners:{  
            beforeselect: function(comboxtree,newNode,oldNode){//选择树结点设值之前的事件  
                alert("beforeselect");
            },  
            select: function(comboxtree,newNode,oldNode){//选择树结点设值之后的事件  
             alert("select");
            },  
            afterchange: function(comboxtree,newNode,oldNode){//选择树结点设值之后,并当新值和旧值不相等时的事件  
             alert("afterchange");
            }  
      }  
});为什么这样,我操作的时候没有一个事件触发,各位帮忙看一上,在线等待。