Ups! Sorry, I forgot to check the major mode.

diff --git a/contrib/slime-fontifying-fu.el b/contrib/slime-fontifying-fu.el

index f99ef43..15d2bba 100644

--- a/contrib/slime-fontifying-fu.el

+++ b/contrib/slime-fontifying-fu.el

@@ -57,7 +57,8 @@ string to highlight using FACE.")

 

 (defun slime-hack-local-variables ()

   (let ((local-keywords (mapcar 'slime-keyword-spec slime-local-keywords)))

-    (font-lock-add-keywords nil local-keywords)))

+    (when (eq major-mode 'lisp-mode)

+      (font-lock-add-keywords nil local-keywords))))

 

 ;;;; Specially fontify forms suppressed by a reader conditional.