title: Doctrine 2 result caching in Symfony with form type entity
body: <p>I use APC result caching in docrine, and have filter form with type entity in all website pages and want cache this, but when I add useResultCache() to method I get exception </p>
  
  <blockquote>
    <p>Entities passed to the choice field must be managed</p>
    
    <p>example
    ...->getQuery()->useResultCache(true, null, 'someindex')->getResult()</p>
  </blockquote>
  
  <p>but all action without <code>form</code> with <code>entity type</code> work normally.</p>
  
  <p>Any ideas?</p>