grid example

HTML

<script src="http://cdn.sencha.io/ext-4.2.0-gpl/ext-all-dev.js"></script>
<link rel="stylesheet" href="http://cdn.sencha.io/ext-4.2.0-gpl/resources/css/ext-all.css">

JavaScript

Ext.onReady(function () {
    //to be able to use the ajax simulator
    Ext.Loader.setConfig({
        disableCaching: false,
        enabled: true,
        paths: {
            'Ext.ux': 'http://cdn.sencha.io/ext-4.2.0-gpl/examples/ux'
        }
    });
    //just a model
    Ext.define('Ceres.model.Folder', {
        extend: 'Ext.data.Model',

        fields: [{
            name: 'id'
        }, {
            name: 'name'
        }, {
            name: 'type'
        }]
    });
    //just a store
    Ext.define('Ceres.store.FolderList', {
        extend: 'Ext.data.Store',
        requires: ['Ceres.model.Folder'],

        constructor: function (cfg) {
            var me = this;
            cfg = cfg || {};
            me.callParent([Ext.merge({
                model: 'Ceres.model.Folder',
                proxy: {
                    type: 'ajax',
                    api: {
                        read: "http://localhost/mockdata.php"
                    },
                    reader: {
                        type: 'json',
                        data: 'data',
                        messageProperty: 'message'
                    }
                }
            },
            cfg)]);
        }
    });
    //2 store instances
    var storeA = Ext.create('Ceres.store.FolderList'),
        storeB = Ext.create('Ceres.store.FolderList');
    //view definition
    Ext.define('Ceres.view.FolderList', {
        extend: 'Ext.window.Window',
        alias: 'widget.folderlist',

        requires: ['Ceres.store.FolderList'],

        height: 800,
        width: 600,
        layout: {
            type: 'fit'
        },
        modal: true,
        closeAction: 'hide',
        enableLocking: true, //locking enabled!
        
        initComponent: function () {
            var me = this;

            Ext.applyIf(me, {
                items: [{
                    xtype: 'grid',
                    store: storeA,
                    columns: [
                        {
     ...