title: Extjs4 display tooltip for disabled button
body: <p>when i disable the button it's tooltip also disables. Is there a way to show the tooltip even the button is disabled.</p>
  
  <pre><code>//create my button
         var myButton = Ext.create('Ext.Button', {
              tooltip :  'my Button Tooltip Text',
              id : 'my-button ',
              iconCls : 'star-icon',
              handler: Ext.Function.pass(_rmp.mediaManager.myButtonFunction, this)
          });
  
   //disable my button
      Ext.getCmp('my-button').disable();
  </code></pre>
  
  <p>EDIT:
  It is not working as expected on firefox(I am using version 8.0.1) for other browsers(chrome,safari, opera) tooltip works as expected.</p>