easyui-combox(tagbox) 多选操作显示为tagbox

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" type="text/css" href="./common-static/css/themes/default/easyui.css">
    <link rel="stylesheet" type="text/css" href="./common-static/css/themes/icon.css">
</head>
<body>
 
<input id="tb" type="text" style="width:300px"> 
 
<script src="./common-static/js/jquery.min.js"></script>
<script src="./common-static/js/jquery.easyui.min.js"></script>
<script src="./common-static/js/easyui-lang-zh_CN.js"></script>
 
<script>
    $('#tb').combobox({    
        valueField: 'id',    
        textField: 'text',    
        data: [{    
                "id":1,    
                "text":"text1"
            },{    
                "id":2,    
                "text":"text2",
                "selected":true 
            },{    
                "id":3,    
                "text":"text3",
                "selected":true
            },{    
                "id":4,    
                "text":"text4"  
            },{    
                "id":5,    
                "text":"text5"  
            }],
            multiple:true,
            hasDownArrow:true,
            editable:false,
            separator:' , ',
        formatter: function (row) {
            var opts = $(this).combobox('options');
            return '<input type="checkbox" class="combobox-checkbox">' + row[opts.textField]
        },
 
        onShowPanel: function () {
            var opts = $(this).combobox('options');
            var target = this;
            var values = $(target).combobox('getValues');
            $.map(values, function (value) {
                var el = opts.finder.getEl(target, value);
                el.find('input.combobox-checkbox')._propAttr('checked', true);
            })
        },
        onLoadSuccess: function () {
            var opts = $(this).combobox('options');
            var target = this;
            var values = $(target).combobox('getValues');
            $.map(values, function (value) {
                var el = opts.finder.getEl(target, value);
                el.find('input.combobox-checkbox')._propAttr('checked', true);
            })
        },
        onSelect: function (row) {
            var opts = $(this).combobox('options');
            var el = opts.finder.getEl(this, row[opts.valueField]);
            el.find('input.combobox-checkbox')._propAttr('checked', true);
        },
        onUnselect: function (row) {
             
            var opts = $(this).combobox('options');
            var el = opts.finder.getEl(this, row[opts.valueField]);
            el.find('input.combobox-checkbox')._propAttr('checked', false);
        }
    })
</script>
</body>
</html>