(make-variable-buffer-local 'show-trailing-whitespace)
(defcustom show-trailing-whitespace nil
- "*Non-nil means highlight trailing whitespace in face `trailing-whitespace'."
+ "*Non-nil means highlight trailing whitespace in face `trailing-whitespace'.
+
+Setting this variable makes it local to the current buffer."
:tag "Highlight trailing whitespace."
:set #'(lambda (symbol value) (set-default symbol value))
:type 'boolean