Wijmo 5 - Multi-Column ComboBoxes

HTML

<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css">
<link rel="stylesheet" href="http://cdn.wijmo.com/5.latest/styles/wijmo.min.css">
<script src="http://cdn.wijmo.com/5.latest/controls/wijmo.min.js"></script>
<script src="http://cdn.wijmo.com/5.latest/controls/wijmo.input.min.js"></script>
<script src="http://cdn.wijmo.com/5.latest/controls/wijmo.grid.min.js"></script>
<script src="http://cdn.wijmo.com/5.latest/controls/wijmo.chart.min.js"></script>
<script src="http://cdn.wijmo.com/5.20172.359/controls/wijmo.pdf.min.js"></script>
<script src="http://cdn.wijmo.com/5.20172.359/controls/wijmo.grid.pdf.min.js"></script>
<div class="container" style="width:700px;height:400px;">   
      <div id="grid"></div> 
      <button onclick="exportToPDF();">Export PDF</button>
</div>

CSS

.redRow {
    background-color:rgb(250, 210, 210) !important;
    color:black !important;
}

JavaScript

window.onload = function () { 
 var data = [
        { id: 0, country: "US", sales: 489.51, expenses: 2358.24, product: "Computer"  },
        { id: 1, country: "Deutschland", sales: 7803.20, expenses: 2513.54, product: "Computer" },
        { id: 2, country: "GBR", sales: 9996.58, expenses: 2616.71, product: "Stereo" },
        { id: 3, country: "Japan", sales: 9351.68, expenses: 3030.59, product: "Stereo"  },
        { id: 4, country: "Spanien", sales: 349.51, expenses: 7358.24, product: "Phone" },
        { id: 5, country: "Estland", sales: 500.0, expenses: 4444.4, product: "Camera" },
        { id: 1, country: "Deutschland", sales: 9349, expenses: 23543, product: "Stereo" },
        { id: 0, country: "Ă„gypten", sales: 23423, expenses: 34634, product: "Computer" },
        { id: 0, country: "Kanada", sales: 489.51, expenses: 2358.24, product: "Computer"  },
        { id: 0, country: "US", sales: 489.51, expenses: 2358.24, product: "Computer" },
        { id: 0, country: "US", sales: 489.51, expenses: 2358.24, product: "Computer" },
        { id: 4, country: "Spanien", sales: 349.51, expenses: 7358.24, product: "Phone" },
        { id: 4, country: "Spanien", sales: 349.51, expenses: 7358.24, product: "Phone" },
        { id: 4, country: "Spanien", sales: 349.51, expenses: 7358.24, product: "Phone" },
        { id: 4, country: "Spanien", sales: 349.51, expenses: 7358.24, product: "Phone" }
    ];

    ///****** Grid ******/

    // Grid
    var grid = new wijmo.grid.FlexGrid('#grid', {
        allowMerging: 'ColumnHeaders',
        showAlternatingRows: false,
        autoGenerateColumns: false,
        columns: [
            { binding: "id", header: "ID", visible: false },
            { binding: "country", header: "Land"},
            { binding: "sales", header: "Umsatz" },
            { binding: "expenses", header: "Kosten" },
            { binding: "product", header: "Produkt"}
        ],
       
        
 
    });
    
    grid.loadedRows.addHandler(function...