diff --git a/tinybrowser.module b/tinybrowser.module
index 9849765..89eb133 100644
--- a/tinybrowser.module
+++ b/tinybrowser.module
@@ -306,7 +306,7 @@ function tinybrowser_role_form($role, $weight = TRUE, $core = TRUE) {
     ) : array(
       '#type' => 'weight',
       '#default_value' => $role['weight'],
-      '#attributes' => array('class' => 'tinybrowser-weight'),
+      '#attributes' => array('class' => array('tinybrowser-weight')),
     );
   }
   $options = array(t('none'));