Further tweak previous change

diff --git a/lisp/frame.el b/lisp/frame.el
index bd023dae37c4e06686f0105c39da0a492801e0eb..3668f24ba01a6464ff763621182d602caa588df4 100644 (file)
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -875,7 +875,8 @@ Set this to the symbol `dark' if your background color is dark,
 if you want Emacs to examine the brightness for you.
 
 If you change this without using customize, you should use
-`frame-set-background-mode' to update existing frames."
+`frame-set-background-mode' to update existing frames;
+e.g. (mapc 'frame-set-background-mode (frame-list))."
   :group 'faces
   :set #'(lambda (var value)
           (set-default var value)