KendoUI Grid & Modal Layout Issue

HTML

<link rel="stylesheet" href="http://cdn.kendostatic.com/2013.3.1119/styles/kendo.common.min.css">
<link rel="stylesheet" href="http://cdn.kendostatic.com/2013.3.1119/styles/kendo.default.min.css">
<script src="http://cdn.kendostatic.com/2014.1.318/js/kendo.all.min.js"></script>
<div id="grid">

JavaScript

$(document).ready(function () 
                  {
            
			//DataSource definition
			var crudServiceBaseUrl = "http://demos.kendoui.com/service",
				dataSource = new kendo.data.DataSource({
					transport: {
						read: {
							url: crudServiceBaseUrl + "/Products",
							dataType: "jsonp"
						},
						update: {
							url: crudServiceBaseUrl + "/Products/Update",
							dataType: "jsonp"
						},
						destroy: {
							url: crudServiceBaseUrl + "/Products/Destroy",
							dataType: "jsonp"
						},
						create: {
							url: crudServiceBaseUrl + "/Products/Create",
							dataType: "jsonp"
						},
						parameterMap: function (options, operation) {
							if (operation !== "read" && options.models) {
								return {
									models: kendo.stringify(options.models)
								};
							}
						}
					},
					batch: true,
					pageSize: 20,
					schema: {
						model: {
							id: "ProductID",
							fields: {
								ProductID: {
									editable: false,
									nullable: true
								},
								ProductName: {
									validation: {
										required: true
									}
								},
								UnitPrice: {
									type: "number",
									validation: {
										required: true,
										min: 1
									}
								},
								Discontinued: {
									type: "boolean"
								},
								UnitsInStock: {
									type: "number",
									validation: {
										min: 0,
										required: true
									}
								}
							}
						}
					}
				});

			//Grid definition
			var grid = $("#grid").kendoGrid({
				dataSource: dataSource,
				pageable: true,
				height: 430,
				//define dataBound event handler
				dataBound: onDataBound,
				navigatable: true,
				columns: [
					//define template column with checkbox and attach click event handler
					{ template: "<input type='checkbox' class='checkbox' tabindex='-1' />",
                     headerTemplate: "<span class='k-link' /><input type='checkbox' class='checkbox' tabindex='-1' />"},
					"ProductName",...