Edit in JSFiddle

var pop = new wijmo.input.Popup('#message', {
    modal: true,
});

var grid = new wijmo.grid.FlexGrid('#FlexGrid');
grid.itemsSource = createData(5);

var filter = new wijmo.grid.filter.FlexGridFilter(grid);

function createData(count) {
    var countries = 'US,Germany,UK,Japan,Italy,Greece'.split(','),
        data = [];

    for (var i = 0; i < count; i++) {
        data.push({
            id: i + 1,
            country: countries[i % countries.length],
            date: new Date(2014, i % 12, i % 28),
            amount: Math.random() * 10000,
            active: i % 4 == 0
        });
    }

    return data;
}

function btn_click1(e, args) {
    pop.show();
}

<div id="message">
    <div id="FlexGrid"></div>
</div>
<button onclick="btn_click1()">ポップアップを表示</button>