diff --git a/uc_cart/uc_cart.pages.inc b/uc_cart/uc_cart.pages.inc
index 4512e7b..2b23977 100644
--- a/uc_cart/uc_cart.pages.inc
+++ b/uc_cart/uc_cart.pages.inc
@@ -179,8 +179,10 @@ function uc_cart_checkout_form($form, &$form_state) {
           '#description' => !empty($return['description']) ? $return['description'] : NULL,
           '#collapsible' => $pane['collapsible'],
           '#collapsed' => variable_get('uc_use_next_buttons', FALSE) ? $collapsed : FALSE,
-          '#id' => $pane['id'] . '-pane',
           '#theme' => isset($return['theme']) ? $return['theme'] : NULL,
+          '#attributes' => array(
+            'id' => $pane['id'] . '-pane',
+          ),
         );
 
         // Add the contents of the fieldset if any were returned.