title: Extjs 4.2.1 Scroll to selection in combo drop down list
body: <p>In extjs 4.2.1, there is some problem with combobox. When drop down list appears, i need to scroll to selected value, not only highlight it. So if selected value is on bottom, scroll remains on top anyways.
  Here is my code:</p>
  
  <pre><code>Ext.define('FpoApp.store.exams.Courses', {
      extend: 'Ext.data.Store',
      model: 'FpoApp.model.Idname',
      proxy: {
          type: 'ajax',
          url: 'php/exams/getCourses.php',
          reader: {
              type: 'json',
              root: 'rows'
          }
      },
      autoLoad: true
  });
  
  Ext.create('Ext.form.field.ComboBox', {
      queryMode: 'local',
      editable: false,
      valueField: 'id',
      displayField: 'name',   
      store: 'exams.Courses' 
  });
  </code></pre>
  
  <p>Also, it seems to work in extjs 3.4.0. Just found an example, where it works perfectly, just as i need. <a href="http://dev.sencha.com/deploy/ext-3.4.0/examples/form/combos.html" rel="nofollow">Here</a> is example. Looks like basic comboboxes, nothing special. Have no idea what's wrong with 4.2.1. And yes, i'm using mvc.</p>