Add some doc

extension/qfq/qfq/helper/HelperFormElement.php

@@ -125,6 +125,7 @@ class HelperFormElement {
 
     /**
      * Build the FE id: <$formId>-<$formElementId>-<$formElementCopy>
+     * Attention: Radio's get's an additional index count as fourth parameter (not here).
      *
      * @param $formId
      * @param $formElementId