json2tree.js

    createTreePanel: function() {
        var store = Ext.create('Ext.data.TreeStore', {
            root: {
                expanded: true
            },
            proxy: {
                type: 'ajax',
                url:  'tree.json'
            }
        });

        this.treePanel = Ext.create('Ext.tree.Panel', {
            id: 'tree-panel',
            retion: 'center',
            width: 230,
            rootVisible: false,
            store: store
        });

        return this.treePanel;
    },

    createMainTabPanel: function() {
        this.mainTabPanel = Ext.create('Ext.tab.Panel', {
        });

        return this.mainTabPanel;
    },