diff --git a/runtime/ftplugin/dune.vim b/runtime/ftplugin/dune.vim
index 86c99c0..6e20a8f 100644
--- a/runtime/ftplugin/dune.vim
+++ b/runtime/ftplugin/dune.vim
@@ -3,8 +3,9 @@
 "              Anton Kochkov       <anton.kochkov@gmail.com>
 " URL:         https://github.com/ocaml/vim-ocaml
 " Last Change:
-"              2018 Nov 3 - Added commentstring (Markus Mottl)
-"              2017 Sep 6 - Initial version (Etienne Millon)
+"              2023 Aug 28 - Added undo_ftplugin (Vim Project)
+"              2018 Nov 03 - Added commentstring (Markus Mottl)
+"              2017 Sep 06 - Initial version (Etienne Millon)
 
 if exists("b:did_ftplugin")
   finish
@@ -18,3 +19,5 @@
 setl comments=:;
 
 setl iskeyword+=#,?,.,/
+
+let b:undo_ftplugin = "setl lisp< cms< com< isk<"