Why is the data in this ExtJS grid not showing?

I've isolated the checkbox grid from this example of ExtJS grids into the following code.

It shows the grid with the headers but not the data:

Firebug shows no Javascript errors.

What do I have to do to get the dummy data to show in the grid?

Ext.onReady(function(){

    Ext.QuickTips.init();

    var xg = Ext.grid;

    var reader = new Ext.data.ArrayReader({}, [
        {name: 'company'},
        {name: 'price', type: 'float'},
        {name: 'change', type: 'float'},
        {name: 'pctChange', type: 'float'},
        {name: 'lastChange', type: 'date', dateFormat: 'n/j h:ia'},
        {name: 'industry'},
        {name: 'desc'}
    ]);

    var sm = new xg.CheckboxSelectionModel();

    var grid2 = new xg.GridPanel({
        store: new Ext.data.Store({
            reader: reader,
            data: xg.dummyData
        }),
        cm: new xg.ColumnModel({
            defaults: {
                width: 120,
                sortable: true
            },
            columns: [
                sm,
                {id:'company',header: "Company", width: 200, dataIndex: 'company'},
                {header: "Price", renderer: Ext.util.Format.usMoney, dataIndex: 'price'},
                {header: "Change", dataIndex: 'change'},
                {header: "% Change", dataIndex: 'pctChange'},
                {header: "Last Updated", width: 135, renderer: Ext.u开发者_如何学编程til.Format.dateRenderer('m/d/Y'), dataIndex: 'lastChange'}
            ]
        }),
        sm: sm,
        columnLines: true,
        width:800,
        height:300,
        frame:true,
        title:'Framed with Checkbox Selection and Horizontal Scrolling',
        iconCls:'icon-grid',
        renderTo: document.body
    });

    Ext.grid.dummyData = [
        ['3m Co',71.72,0.02,0.03,'9/1 12:00am', 'Manufacturing'],
        ['Alcoa Inc',29.01,0.42,1.47,'9/1 12:00am', 'Manufacturing'],
        ['Altria Group Inc',83.81,0.28,0.34,'9/1 12:00am', 'Manufacturing'],
        ['American Express Company',52.55,0.01,0.02,'9/1 12:00am', 'Finance'],
        ['American International Group, Inc.',64.13,0.31,0.49,'9/1 12:00am', 'Services'],
        ['AT&T Inc.',31.61,-0.48,-1.54,'9/1 12:00am', 'Services'],
        ['Boeing Co.',75.43,0.53,0.71,'9/1 12:00am', 'Manufacturing'],
        ['Caterpillar Inc.',67.27,0.92,1.39,'9/1 12:00am', 'Services'],
        ['Citigroup, Inc.',49.37,0.02,0.04,'9/1 12:00am', 'Finance'],
        ['E.I. du Pont de Nemours and Company',40.48,0.51,1.28,'9/1 12:00am', 'Manufacturing'],
        ['Exxon Mobil Corp',68.1,-0.43,-0.64,'9/1 12:00am', 'Manufacturing'],
        ['General Electric Company',34.14,-0.08,-0.23,'9/1 12:00am', 'Manufacturing'],
        ['General Motors Corporation',30.27,1.09,3.74,'9/1 12:00am', 'Automotive'],
        ['Hewlett-Packard Co.',36.53,-0.03,-0.08,'9/1 12:00am', 'Computer'],
        ['Honeywell Intl Inc',38.77,0.05,0.13,'9/1 12:00am', 'Manufacturing'],
        ['Intel Corporation',19.88,0.31,1.58,'9/1 12:00am', 'Computer'],
        ['International Business Machines',81.41,0.44,0.54,'9/1 12:00am', 'Computer'],
        ['Johnson & Johnson',64.72,0.06,0.09,'9/1 12:00am', 'Medical'],
        ['JP Morgan & Chase & Co',45.73,0.07,0.15,'9/1 12:00am', 'Finance'],
        ['McDonald\'s Corporation',36.76,0.86,2.40,'9/1 12:00am', 'Food'],
        ['Merck & Co., Inc.',40.96,0.41,1.01,'9/1 12:00am', 'Medical'],
        ['Microsoft Corporation',25.84,0.14,0.54,'9/1 12:00am', 'Computer'],
        ['Pfizer Inc',27.96,0.4,1.45,'9/1 12:00am', 'Services', 'Medical'],
        ['The Coca-Cola Company',45.07,0.26,0.58,'9/1 12:00am', 'Food'],
        ['The Home Depot, Inc.',34.64,0.35,1.02,'9/1 12:00am', 'Retail'],
        ['The Procter & Gamble Company',61.91,0.01,0.02,'9/1 12:00am', 'Manufacturing'],
        ['United Technologies Corporation',63.26,0.55,0.88,'9/1 12:00am', 'Computer'],
        ['Verizon Communications',35.57,0.39,1.11,'9/1 12:00am', 'Services'],
        ['Wal-Mart Stores, Inc.',45.45,0.73,1.63,'9/1 12:00am', 'Retail'],
        ['Walt Disney Company (The) (Holding Company)',29.89,0.24,0.81,'9/1 12:00am', 'Services']
    ];

});

Found it: the Ext.grid.dummyData block just has to be defined outside the Ext.onReady(function(){ block.