title: ExtJS setStyle changes for a split second then returns to previous style
body: <p>I have a dataview component with id "alerts" which contains a set of divs with class "alert".</p>
  
  <p>When I use the following:</p>
  
  <pre><code>Ext.getCmp("alerts").getEl().down('.alert').setStyle({background: 'yellow'});
  </code></pre>
  
  <p>The background for the first alert in the dataview changes for a split second and then returns to its previous style.</p>
  
  <p>Can anyone tell me what I am doing wrong?</p>