diff --git a/domain_settings/domain_settings.module b/domain_settings/domain_settings.module
index 265da4c..394e7c8 100644
--- a/domain_settings/domain_settings.module
+++ b/domain_settings/domain_settings.module
@@ -120,7 +120,7 @@ function domain_settings_form_alter(&$form, $form_state, $form_id) {
  * Submit handler for domain-specific settings.
  */
 function domain_settings_form_submit($form, &$form_state) {
-  $domain_id = $form_state['values']['domain_id'];
+  $domain_id = empty($form['#tree']) ? $form_state['values']['domain_id'] : $form_state['values']['domain_settings']['domain_id'];
   $values = array();
   foreach ($form_state['values'] as $key => $value) {
     if (!in_array($key, array('op', 'submit', 'reset', 'form_build_id', 'form_token', 'form_id', 'domain_id'))) {