Update Jqxgrid's Comboxbox Cell Value

How can I update combobox cell value. You can check the code at the following link. When I set 'countryCode' value to 'US', it doesn't make any changes. Should I set the label as well, as shown in the code on line 188? Is this the best approach? Please let me know if there's a better way.

by inee814

HTML

<script src="https://jqwidgets.com/public/jqwidgets/jqx-all.js"></script>
<link rel="stylesheet" href="https://jqwidgets.com/public/jqwidgets/styles/jqx.base.css">
<link rel="stylesheet" href="https://jqwidgets.com/public/jqwidgets/styles/jqx.energyblue.css">
<script src="https://jqwidgets.com/jquery-widgets-demo/demos/jqxgrid/generatedata.js"></script>
<div id='jqxWidget'>
    <div id="jqxgrid"></div>
</div>
<div style="margin-top: 10px;">
    <input id="updaterowbutton" type="button" value="Update Selected Row" />
</div>

JavaScript

var countries = [
    {value: "AF", label: "Afghanistan"},
    {value: "AL", label: "Albania"},
    {value: "DZ", label: "Algeria"},
    {value: "AR", label: "Argentina"},
    {value: "AM", label: "Armenia"},
    {value: "AU", label: "Australia"},
    {value: "AT", label: "Austria"},
    {value: "AZ", label: "Azerbaijan"},
    {value: "BS", label: "Bahamas"},
    {value: "BH", label: "Bahrain"},
    {value: "BD", label: "Bangladesh"},
    {value: "BB", label: "Barbados"},
    {value: "BY", label: "Belarus"},
    {value: "BE", label: "Belgium"},
    {value: "BZ", label: "Belize"},
    {value: "BJ", label: "Benin"},
    {value: "BM", label: "Bermuda"},
    {value: "BR", label: "Brazil"},
    {value: "BN", label: "Brunei"},
    {value: "BG", label: "Bulgaria"},
    {value: "CM", label: "Cameroon"},
    {value: "CA", label: "Canada"},
    {value: "CL", label: "Chile"},
    {value: "CN", label: "China"},
    {value: "CO", label: "Columbia"},
    {value: "CR", label: "Costa Rica"},
    {value: "HR", label: "Croatia (Hrvatska)"},
    {value: "CU", label: "Cuba"},
    {value: "CY", label: "Cyprus"},
    {value: "CZ", label: "Czech Republic"},
    {value: "DK", label: "Denmark"},
    {value: "TP", label: "East Timor"},
    {value: "EC", label: "Ecuador"},
    {value: "EG", label: "Egypt"},
    {value: "ER", label: "Eritrea"},
    {value: "EE", label: "Estonia"},
    {value: "ET", label: "Ethiopia"},
    {value: "FI", label: "Finland"},
    {value: "FR", label: "France"},
    {value: "DE", label: "Germany"},
    {value: "GR", label: "Greece"},
    {value: "HK", label: "Hong Kong"},
    {value: "HU", label: "Hungary"},
    {value: "IS", label: "Iceland"},
    {value: "IN", label: "India"},
    {value: "ID", label: "Indonesia"},
    {value: "IR", label: "Iran"},
    {value: "IQ", label: "Iraq"},
    {value: "IE", label: "Ireland"},
    {value: "IL", label: "Israel"},
    {value: "IT", label: "Italy"},
    {value: "JM", label: "Jamaica"},
    {value: "JP", label: "Japan"},
  ...