JSGrid Update Item Fail Issue

HTML

<link rel="stylesheet" href="http://js-grid.com/css/jsgrid.min.css">
<link rel="stylesheet" href="http://js-grid.com/css/jsgrid-theme.min.css">
<script src="http://js-grid.com/js/jsgrid.min.js"></script>
<script src="http://underscorejs.org/underscore-min.js"></script>
<link rel="stylesheet" href="https://code.jquery.com/ui/1.10.4/themes/redmond/jquery-ui.css">
<script src="https://code.jquery.com/ui/1.11.2/jquery-ui.js"></script>
<div id="jsGrid"></div>

JavaScript

var db = window.db = {};

db.countries = [
    { Name: "", Id: 0 },
    { Name: "United States", Id: 1 },
    { Name: "Canada", Id: 2 },
    { Name: "United Kingdom", Id: 3 },
    { Name: "France", Id: 4 },
    { Name: "Brazil", Id: 5 },
    { Name: "China", Id: 6 },
    { Name: "Russia", Id: 7 }
];

db.clients = [
    {
        "Name": "Otto Clay",
        "Age": 61,
        "Country": 6,
        "Address": "Ap #897-1459 Quam Avenue",
        "Married": false
    },
    {
        "Name": "Connor Johnston",
        "Age": 73,
        "Country": 7,
        "Address": "Ap #370-4647 Dis Av.",
        "Married": false
    },
    {
        "Name": "Lacey Hess",
        "Age": 29,
        "Country": 7,
        "Address": "Ap #365-8835 Integer St.",
        "Married": false
    },
    {
        "Name": "Timothy Henson",
        "Age": 78,
        "Country": 1,
        "Address": "911-5143 Luctus Ave",
        "Married": false
    },
    {
        "Name": "Ramona Benton",
        "Age": 43,
        "Country": 5,
        "Address": "Ap #614-689 Vehicula Street",
        "Married": true
    },
    {
        "Name": "Ezra Tillman",
        "Age": 51,
        "Country": 1,
        "Address": "P.O. Box 738, 7583 Quisque St.",
        "Married": true
    },
    {
        "Name": "Dante Carter",
        "Age": 59,
        "Country": 1,
        "Address": "P.O. Box 976, 6316 Lorem, St.",
        "Married": false
    },
    {
        "Name": "Christopher Mcclure",
        "Age": 58,
        "Country": 1,
        "Address": "847-4303 Dictum Av.",
        "Married": true
    },
    {
        "Name": "Ruby Rocha",
        "Age": 62,
        "Country": 2,
        "Address": "5212 Sagittis Ave",
        "Married": false
    },
    {
        "Name": "Imelda Hardin",
        "Age": 39,
        "Country": 5,
        "Address": "719-7009 Auctor Av.",
        "Married": false
    },
    {
        "Name": "Jonah Johns",
        "Age": 28,
        "Country": 5,
        "Address": "P.O. Box...