title: how to build an EXTJS4 mvc demo with desktop module
body: <p>My code can load the Model, View, Controller, but the launch function does not work.</p>
  
  <p>I want every icon on the desktop to be a App so it can load the Model, View, Controller when each has been clicked. How to do this?</p>
  
  <pre><code>Ext.define('MyApp.GridWindow', {
      extend: 'Ext.ux.desktop.Module',
  
      requires: [
          'Ext.data.ArrayStore',
          'Ext.util.Format',
          'Ext.grid.Panel',
          'Ext.grid.RowNumberer'
      ],
  
      id:'grid-win',
  
      init : function(){
          this.launcher = {
              text: 'Grid Window',
              iconCls:'icon-grid',
              handler : this.createWindow,
              scope: this
          };
      },
  
      createWindow : function(){
          var desktop = this.app.getDesktop();
          var win = desktop.getWindow('grid-win');
  
          if(!win){
  
            Ext.application({
                name: 'USER',
                appFolder: PUB+'/extjs4/mUser',
                controllers: [
                    "User"
                ],
                launch: function () {
                    win = desktop.createWindow({
                        id: 'notepad',
                        title:'Notepad',
                        width:600,
                        height:400,
                        iconCls: 'notepad',
                        animCollapse:false,
                        border: false,
                        hideMode: 'offsets',
                        layout: 'fit',
                        items: [{
                            xtype: 'htmleditor',
                            //xtype: 'textarea',
                            id: 'notepad-editor'
                         }]
                     });
                 }
          });
  
          win.show();
          return win;
  },
  </code></pre>