--- /tmp/themesettingsapi.admin.inc	2010-06-22 15:47:49.000000000 -0600
+++ themesettingsapi.admin.inc	2010-06-23 10:41:46.000000000 -0600
@@ -100,8 +100,7 @@
         if (function_exists($function)) {
           $group = $function($settings);
           if (!empty($group)) {
-            $form['engine_specific'] = array('#type' => 'fieldset', '#title' => t('Theme-engine-specific settings'), '#description' => t('These settings only exist for all the templates and styles based on the %engine theme engine.', array('%engine' => $themes[$key]->prefix)));
-            $form['engine_specific'] = array_merge($form['engine_specific'], $group);
+            $form = array_merge_recursive($form, $group);
           }
         }
 
@@ -113,8 +112,7 @@
         if (function_exists($function)) {
           $group = $function($settings);
           if (!empty($group)) {
-            $form['theme_specific'] = array('#type' => 'fieldset', '#title' => t('Theme-specific settings'), '#description' => t('These settings only exist for the %theme theme and all the styles based on it.', array('%theme' => $key)));
-            $form['theme_specific'] = array_merge($form['theme_specific'], $group);
+            $form = array_merge_recursive($form, $group);
           }
         }
       }