title: How to disable action column item for a single row?
body: <p>Consider this JSON sample :</p>
  
  <pre><code>[{id:1,editable:true},{id:2,editable:false}]
  </code></pre>
  
  <p>These records are about to be loaded in a store, then displayed inside a grid panel. This grid has an action column item for edition purposes. I'm looking for a way to disable the "edit" button only for the second row without performing computation after rendering. I'd like to use a built in feature which works like the <a href="http://docs.sencha.com/ext-js/4-1/#!/api/Ext.grid.column.Column-cfg-renderer" rel="noreferrer"><code>renderer</code></a> property rather than to loop through the store to update each row once the grid has been rendered. </p>
  
  <p>Does ExtJS 4.1.1 provides this kind of feature?</p>