diff --git a/theme/theme.inc b/theme/theme.inc
index e7f7a15..1f6f58f 100644
--- a/theme/theme.inc
+++ b/theme/theme.inc
@@ -326,7 +326,7 @@ function theme_views_view_grouping($vars) {
  * Process a single grouping within a view.
  */
 function template_preprocess_views_view_grouping(&$vars) {
-  $vars['content'] = $vars['view']->style_plugin->render_grouping_sets($vars['rows'], $vars['grouping_level']);
+  $vars['content'] = $vars['view']->style_plugin->render_grouping_sets($vars['rows'], $vars['grouping_level'] + 1);
 }
 
 /**