diff --git a/booking.variety_form.inc b/booking.variety_form.inc
index d70d0b1..2eeeac4 100644
--- a/booking.variety_form.inc
+++ b/booking.variety_form.inc
@@ -152,7 +152,7 @@ function booking_variety_session_form_callback($form, &$form_state) {
     }
     else {
       $form['form']['identity']['booking_feedback_wrapper']['#markup'] = '<div id="booking_feedback_wrapper">Identity matched.</div>';
-      $form['form']['variety-sessions']['#attributes']['class'][] = '';
+      $form['form']['variety-sessions']['#attributes']['class'] = '';
     }
   }