title: Symfony validate form with mapped false form fields
body: <p>I've got a form with extra fields added with the option <code>mapped</code> to <code>false</code>. But when I try to validate my form, it won't pass indicating "this value is not valid" above these specific form fields. Isn't this option supposed to bypass validation? </p>
  
  <p>These form fields are only useful for populate other fields and I don't need to save or even check them. </p>
  
  <p>The only solution I found is to remove all extra fields with js on a submit button click. </p>