title: put shadow on window extjs
body: <p>I want to put shadow on this window, I tried a lot of variants, but nothing.</p>
  
  <pre><code>var win;
  var button;  
  
  function wind(cerand) {
  
      button = Ext.get('show-btn' + cerand);
  
      if(!win) {
          win = new Ext.Window({
              applyTo: 'hello-win' + cerand,
              layout: 'fit',
  
              closeAction: 'hide',
              plain: true,
              html: 'hello-win' + cerand,
              width: '400',
              height: '300',
              items: new Ext.FormPanel({
                  applyTo: 'hello-tabs' + cerand
              }),
  
              buttons: [{
                  text: 'Close',
                  handler: function() {
                      win.hide();
                  }
              }]
          });
      }
      win.alignTo(document, 'c-c', [0, -10]);
      win.show(button);
  };
  </code></pre>