ExtJs面向对象错误

this.ComboFunction=new Business.sys.ComboFunction({

id:'FunctionId',

key:'FunctionId'

});

GM.FormItem= function(config){

this.config = config||{};

this.ComboFunction=new Business.sys.ComboFunction({

id:'FunctionId',

key:'FunctionId'

});

var defConfig = {

frame: true,

labelWidth: 100,

defaults: {

layout: "form",

xtype: 'textfield'

},

items:[{

key:'ID',

fieldLabel: '帮助ID',

allowBlank:true,

readOnly:true

},{

key:'SortId',

xtype:'hidden'

},{

fieldLabel: '标题',

allowBlank:false,

maxLength:36,

key: 'Title'

},{

fieldLabel: '所属类别',

maxLength:36,

readOnly:true,

key: 'SortTitle'

},{

fieldLabel: '关键字',

maxLength:36,

key: 'Keywords'

},this.ComboFunction,{

hideLabel:true,

fieldLabel: '内容',

xtype:'bhtmleditor',

height:500,

key: 'Content'

}]

};

Ext.applyIf(this.config, defConfig);

GM.FormItem.superclass.constructor.call(this, this.config);alert(this.ComboFunction);

}

在创建窗体第一次显示，第二次以后就不显示combo