When I config grid enableLocking to false, the grid is empty. In Ext.grid.plugin.RowExpander, there is a condition in setCmp function that check grid is locking enabled. I remove that condition and the RowExpander work without needing grid to be locking.

It would be wonderful if grid does not need to locking before we can use RowExpander.

Code:
    Ext.Loader.setConfig({
        enabled: true
    });


    Ext.require([
        'Ext.grid.*',
        'Ext.data.*',
        'Ext.selection.CheckboxModel'
    ]);


    Ext.onReady(function(){
        Ext.define('Company', {
            extend: 'Ext.data.Model',
            fields: [
                {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'}
            ]
        });
        // Array data for the grids
        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', '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']
        ];


        // add in some dummy descriptions
        for(var i = 0; i < Ext.grid.dummyData.length; i++){
            Ext.grid.dummyData[i].push('Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Sed metus nibh, sodales a, porta at, vulputate eget, dui. Pellentesque ut nisl. ');
        }




        Ext.QuickTips.init();


        var getLocalStore = function() {
            return Ext.create('Ext.data.ArrayStore', {
                model: 'Company',
                data: Ext.grid.dummyData
            });
        };




        ////////////////////////////////////////////////////////////////////////////////////////
        // Grid 1
        ////////////////////////////////////////////////////////////////////////////////////////
        // row expander


        var grid1 = Ext.create('Ext.grid.Panel', {
            store: getLocalStore(),
            columns: [
                {text: "Company", flex: 1, dataIndex: 'company'},
                {text: "Price", renderer: Ext.util.Format.usMoney, dataIndex: 'price'},
                {text: "Change", dataIndex: 'change'},
                {text: "% Change", dataIndex: 'pctChange'},
                {text: "Last Updated", renderer: Ext.util.Format.dateRenderer('m/d/Y'), dataIndex: 'lastChange'}
            ],
            enableLocking: false,
            width: 600,
            height: 300,
            plugins: [{
                ptype: 'rowexpander',
                rowBodyTpl : new Ext.XTemplate(
                        '<p><b>Company:</b> {company}</p>',
                        '<p><b>Change:</b> {change:this.formatChange}</p><br>',
                        '<p><b>Summary:</b> {desc}</p>',
                        {
                            formatChange: function(v){
                                var color = v >= 0 ? 'green' : 'red';
                                return '<span style="color: ' + color + ';">' + Ext.util.Format.usMoney(v) + '</span>';
                            }
                        })
            }],
            collapsible: true,
            animCollapse: false,
            title: 'Expander Rows in a Collapsible Grid with lockable columns',
            iconCls: 'icon-grid',
            margin: '0 0 20 0',
            renderTo: Ext.getBody()
        });
    });