diff --git a/doc/emacs/frames.texi b/doc/emacs/frames.texi
index a171db7bb03..95b721fa739 100644
--- a/doc/emacs/frames.texi
+++ b/doc/emacs/frames.texi
@@ -329,6 +329,7 @@ instead of running the @code{mouse-save-then-kill} command, rebind
 @kbd{Mouse-3} by adding the following line to your init file
 (@pxref{Init Rebinding}):
 
+@c FIXME: `mouse-popup-menubar-stuff' is obsolete since 23.1.
 @smallexample
 (global-set-key [mouse-3] 'mouse-popup-menubar-stuff)
 @end smallexample
diff --git a/doc/lispintro/emacs-lisp-intro.texi b/doc/lispintro/emacs-lisp-intro.texi
index 22e50e94f48..245113b86d7 100644
--- a/doc/lispintro/emacs-lisp-intro.texi
+++ b/doc/lispintro/emacs-lisp-intro.texi
@@ -3454,6 +3454,9 @@ a function.  (@xref{Interactive Codes, , Code Characters for
 Consider the function @code{zap-to-char}.  Its interactive expression
 is
 
+@c FIXME: the interactive expression of zap-to-char has been changed
+@c (in 2012-04-10).
+
 @smallexample
 (interactive "p\ncZap to char: ")
 @end smallexample