EXT中复选框横排

刚参加工作，接触EXT，感觉挺难的，下边是我这几天我遇到的复选框横排问题：

//显示的有复选框的FormPanel
var empinfostepForm =new Ext.FormPanel({
frame:true,
         layout:"form",
title:'办理步骤',
buttonAlign : 'center',
//下边这些是使复选框“横排”
items:[{
xtype:"panel",
layout:"column",//也可以是table,实现多列布局
fieldLabel:'步骤1',
isFormField:true,//非常重要,否则panel默认不显示fieldLabel
items:[
{
                               columnWidth:.2,//宽度为50%
                               xtype:"checkbox",
                               boxLabel:"收集材料",//显示在复选框右边的文字
                                    name:""
             }]
},

{
                           xtype:"panel",
    layout:"column",//也可以是table,实现多列布局
     fieldLabel:'步骤2',
                                isFormField:true,//非常重要,否则panel默认不显示fieldLabel
                                items: [{
columnWidth : .2,
boxLabel: '接收审定相关材料',
name: '',
xtype: 'checkbox'
}]
        },{
              xtype:"panel",
                  layout:"column",//也可以是table,实现多列布局
                     fieldLabel:'步骤3',
                  isFormField:true,//非常重要,否则panel默认不显示fieldLabel
                 items: [{
columnWidth : .2,
boxLabel: '补交材料',
name: '',
xtype: 'checkbox'
}]
       }],
   buttons:[butt]  
  });