diff --git a/lisp/ps-samp.el b/lisp/ps-samp.el
index fdff0f182db..22a29b8b4b1 100644
--- a/lisp/ps-samp.el
+++ b/lisp/ps-samp.el
@@ -1,4 +1,4 @@
-;;; ps-samp.el --- ps-print sample setup code
+;;; ps-samp.el --- ps-print sample setup code  -*- lexical-binding: t -*-
 
 ;; Copyright (C) 2007-2021 Free Software Foundation, Inc.