private function assertFieldIsReadable(Tracker_FormElement $field, User $user)
 {
     if (!($field->userCanRead($user) && $field->getTracker()->userCanView($user))) {
         $exception_message = $GLOBALS['Language']->getText('plugin_tracker_formelement_exception', 'permission_denied');
         throw new Exception($exception_message);
     }
 }
 protected function userCanReadSharedField(PFUser $user, Tracker_FormElement $field)
 {
     return $field->userCanRead($user) && $this->canReadAllTargets($user, $field);
 }