diff --git a/docs/mkdocs_parent.yml b/docs/mkdocs_parent.yml
index f7e79e0..6cd6597 100644
--- a/docs/mkdocs_parent.yml
+++ b/docs/mkdocs_parent.yml
@@ -39,6 +39,7 @@ theme:
     - navigation.instant
     - navigation.instant.prefetch
     - navigation.instant.progress
+    - navigation.indexes
     - search.share
     - search.suggest
     - content.tooltips