title: ZF2 refresh input filter after dynamicly adding elements to form
body: <p>I have a form that triggers on event in <code>__construct</code> method to load some items from another modules . So far so good , a field set is loaded from the other module and added to the form and in the <code>request-&gt;getPost()</code> I have the data for the elements inside the fieldset , but the <code>$form-&gt;getData()</code>  doesn't have the data for the fieldset.</p>
  
  <p>I am calling <code>$form-&gt;getInputFilter()</code> before adding this fieldsets to the form and it seems that calling the <code>$form-&gt;getInputFilter()</code> dosn't creates the filters for the newly added elements . so how can i create inputfilters for the dynamic events without recreating the hole filters again ?</p>
  
  <p>Or should i just delay calling <code>$form-&gt;getInputFilter()</code> untill all of the elemnts have been added to the form ?</p>