Fix bug #17532 with unclear docs of setting frame's font.

 lisp/frame.el (set-frame-font): Doc fix.
 lisp/menu-bar.el (menu-set-font): Doc fix.

 doc/emacs/frames.texi (Fonts): Clarify which frames are affected by
 setting font from the menu and in default-frame-alist.

doc/emacs/ChangeLog

+2014-05-21  Eli Zaretskii  <eliz@gnu.org>
+
+	* frames.texi (Fonts): Clarify which frames are affected by
+	setting font from the menu and in default-frame-alist.
+	(Bug#17532)
+
 2014-05-12  Eli Zaretskii  <eliz@gnu.org>
 
 	* mule.texi (Language Environments): Remove unused @anchor.

doc/emacs/frames.texi

@@ -494,13 +494,14 @@ the mouse cursor to the chosen frame.
 @cindex fonts
 
   By default, Emacs displays text on graphical displays using a
-12-point monospace font.  There are several different ways to specify
+10-point monospace font.  There are several different ways to specify
 a different font:
 
 @itemize
 @item
-Click on @samp{Set Default Font} in the @samp{Options} menu.  To save
-this for future sessions, click on @samp{Save Options} in the
+Click on @samp{Set Default Font} in the @samp{Options} menu.  This
+makes the selected font the default on all existing graphical frames.
+To save this for future sessions, click on @samp{Save Options} in the
 @samp{Options} menu.
 
 @item
@@ -513,6 +514,10 @@ Add a line to your init file, modifying the variable
              '(font . "DejaVu Sans Mono-10"))
 @end example
 
+@noindent
+This makes the font the default on all graphical frames created after
+restarting Emacs with that init file.
+
 @cindex X defaults file
 @cindex X resources file
 @item

lisp/ChangeLog

+2014-05-21  Eli Zaretskii  <eliz@gnu.org>
+
+	* frame.el (set-frame-font): Doc fix.
+
+	* menu-bar.el (menu-set-font): Doc fix.  (Bug#17532)
+
 2014-05-21  Dmitry Gutov  <dgutov@yandex.ru>
 
 	* emacs-lisp/package.el (package--download-one-archive): Use

lisp/frame.el

@@ -1107,10 +1107,10 @@ number of lines and columns.
 
 If FRAMES is nil, apply the font to the selected frame only.
 If FRAMES is non-nil, it should be a list of frames to act upon,
-or t meaning all graphical frames.  Also, if FRAME is non-nil,
-alter the user's Customization settings as though the
-font-related attributes of the `default' face had been \"set in
-this session\", so that the font is applied to future frames."
+or t meaning all existing graphical frames.
+Also, if FRAMES is non-nil, alter the user's Customization settings
+as though the font-related attributes of the `default' face had been
+\"set in this session\", so that the font is applied to future frames."
   (interactive
    (let* ((completion-ignore-case t)
 	  (font (completing-read "Font name: "

lisp/menu-bar.el

@@ -662,7 +662,7 @@ by \"Save Options\" in Custom buffers.")
 ;; Function for setting/saving default font.
 
 (defun menu-set-font ()
-  "Interactively select a font and make it the default."
+  "Interactively select a font and make it the default on all existing frames."
   (interactive)
   (set-frame-font (if (fboundp 'x-select-font)
 		      (x-select-font)