title: Can't Load Google Map with GMapPanel - EXTJS 4
body: <pre><code>Ext.Loader.setPath('Ext.ux', '../ux');
  Ext.require([
      'Ext.tree.*',
      'Ext.data.*',
      'Ext.window.MessageBox',
      'Ext.window.*',
      'Ext.ux.GMapPanel'
  ]);
  
  var map = new Ext.ux.GMapPanel({
              xtype: 'gmappanel',
              region: 'center',
              id:  'mygooglemap',
              zoomLevel: 3,
              gmapType: 'map',
              setCenter: {
                  'lat': 37.4419,
                  'lng': -122.1419
              }
          });
  
      var layout = Ext.create('Ext.panel.Panel', {
              //renderTo: 'layout',
              width: window.innerWidth,
              height: window.innerHeight,
              //title: 'Border Layout', //no title will be blank
              layout: 'border',
              items: [{
                  title: 'Message List',
                  region: 'south',     // position for region
                  xtype: 'panel',
                  height: 100,
                  split: true,         // enable resizing
                  collapsible: true,
                  margins: '0 5 5 5',
                  collapsed: true
              },tree,map],
              renderTo: Ext.getBody() //get the body and display Layout at there
          });
  </code></pre>
  
  <h2>Question</h2>
  
  <p>all load successful, treepanel with name tree also load sucess,just the map GMapPanel can't show the google map,why?please help me,thanks. i have no idea</p>
  
  <p>UPDATE
  this the screenshot i have taken, the page should load google map,but is blank
  <img src="https://i.stack.imgur.com/MAP91.jpg" alt="enter image description here"></p>