[Emacs-diffs] emacs-26 c04b48c: Rewrite documentation of buffer display

[Martin Rudalics]

branch: emacs-26
commit c04b48c0883d839f386a1f2921503837b7673062
Author: Martin Rudalics <address@hidden>
Commit: Martin Rudalics <address@hidden>

    Rewrite documentation of buffer display
    
    * doc/emacs/windows.texi (Window Choice): Rewrite, replacing
    references to older buffer display options with references to
    and examples of buffer display actions.
    (Temporary Displays): Rewrite display of *Completions*
    example.
    
    * doc/lispref/elisp.texi (Top): New Windows section
    'Displaying Buffers'.
    * doc/lispref/frames.texi (Child Frames): Adjust cross
    reference.
    * doc/lispref/windows.texi (Windows): New section 'Displaying
    Buffers'.  Move sections 'Choosing Window', 'Display Action
    Functions' and 'Choosing Window Options' there and adjust
    namings.  Preferably write 'Buffer Display Action' instead of
    'Display Action'.  More consistently use @w{} to make key
    binding specifications unsplittable.
    (Displaying Buffers): New section.
    (Choosing Window): Make it a subsection of 'Displaying
    Buffers'.  More explicitly describe how 'display-buffer'
    compiles its list of action functions and the action alist.
    (Buffer Display Action Functions): Rename from 'Display Action
    Functions', make it a subsection of 'Displaying Buffers' and
    rewrite it.  Elide more detailed descriptions of action alist
    entries; these are now in the new section 'Buffer Display
    Action Functions'.  Remove example.
    (Buffer Display Action Alists): New subsection of 'Displaying
    Buffers' giving a comprehensive description of recognized
    action alist entries with appropriate indexing.  Contents were
    partially moved here from the old 'Display Action Functions'
    section.
    (Choosing Window Options): Make it a subsection of 'Displaying
    Buffers'.  Add examples of how to rewrite old buffer display
    options with the help of buffer display actions.
    (Precedence of Action Functions): New subsection of
    'Displaying Buffers' explaining the execution order of action
    functions with the help of a detailed example.
    (The Zen of Buffer Display): New subsection of 'Displaying
    Buffers' supplying guidelines on how to write and use buffer
    display actions with examples.
    (Side Windows, Displaying Buffers in Side Windows)
    (Frame Layouts with Side Windows, Atomic Windows): Update
    references to the 'Displaying Buffers' subsections.
---
 doc/emacs/windows.texi   |  108 ++--
 doc/lispref/elisp.texi   |   16 +-
 doc/lispref/frames.texi  |   10 +-
 doc/lispref/windows.texi | 1442 ++++++++++++++++++++++++++++++++++++----------
 4 files changed, 1207 insertions(+), 369 deletions(-)

diff --git a/doc/emacs/windows.texi b/doc/emacs/windows.texi
index 7dbd680..b09c9ae 100644
--- a/doc/emacs/windows.texi
+++ b/doc/emacs/windows.texi
@@ -48,8 +48,8 @@ other windows at all.  However, there are other commands such 
as
 @kbd{C-x 4 b} that select a different window and switch buffers in it.
 Also, all commands that display information in a window, including
 (for example) @kbd{C-h f} (@code{describe-function}) and @kbd{C-x C-b}
-(@code{list-buffers}), work by switching buffers in a nonselected
-window without affecting the selected window.
+(@code{list-buffers}), usually work by displaying buffers in a
+nonselected window without affecting the selected window.
 
   When multiple windows show the same buffer, they can have different
 regions, because they can have different values of point.  However,
@@ -340,11 +340,9 @@ heights of all the windows in the selected frame.
 in response to a user command.  There are several different ways in
 which commands do this.
 
-  Many commands, like @kbd{C-x C-f} (@code{find-file}), display the
-buffer by ``taking over'' the selected window, expecting that the
-user's attention will be diverted to that buffer.  These commands
-usually work by calling @code{switch-to-buffer} internally
-(@pxref{Select Buffer}).
+  Many commands, like @kbd{C-x C-f} (@code{find-file}), by default
+display the buffer by ``taking over'' the selected window, expecting
+that the user's attention will be diverted to that buffer.
 
   Some commands try to display intelligently, trying not to take
 over the selected window, e.g., by splitting off a new window and
@@ -367,10 +365,9 @@ key (@pxref{Pop Up Window}).
 
   Commands with names ending in @code{-other-frame} behave like
 @code{display-buffer}, except that they (i) never display in the
-selected window and (ii) prefer to create a new frame to display the
-desired buffer instead of splitting a window---as though the variable
address@hidden is set to @code{t} (@pxref{Window Choice}).
-Several of these commands are bound in the @kbd{C-x 5} prefix key.
+selected window and (ii) prefer to either create a new frame or use a
+window on some other frame to display the desired buffer.  Several of
+these commands are bound in the @kbd{C-x 5} prefix key.
 
 @menu
 * Window Choice::   How @code{display-buffer} works.
@@ -383,33 +380,61 @@ Several of these commands are bound in the @kbd{C-x 5} 
prefix key.
 
 The @code{display-buffer} command (as well as commands that call it
 internally) chooses a window to display by following the steps given
-below.  @xref{Choosing Window,,Choosing a Window for Display, elisp,
-The Emacs Lisp Reference Manual}, for details about how to alter this
-sequence of steps.
+below.  @xref{Choosing Window,,Choosing a Window for Displaying a
+Buffer, elisp, The Emacs Lisp Reference Manual}, for details about how
+to alter this sequence of steps.
 
 @itemize
address@hidden same-window-buffer-names
address@hidden same-window-regexps
 @item
 First, check if the buffer should be displayed in the selected window
 regardless of other considerations.  You can tell Emacs to do this by
-adding the desired buffer's name to the list
address@hidden, or adding a matching regular
-expression to the list @code{same-window-regexps}.  By default, these
-variables are @code{nil}, so this step is skipped.
+adding a regular expression matching the buffer's name together with a
+reference to the @code{display-buffer-same-window} action function
+(@pxref{Buffer Display Action Functions,,Action Functions for Buffer
+Display, elisp, The Emacs Lisp Reference Manual}) to the option
address@hidden (@pxref{Choosing Window,,Choosing a Window
+for Displaying a Buffer, elisp, The Emacs Lisp Reference Manual}).
+For example, to display the buffer @file{*scratch*} preferably in the
+selected window write:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-alist
+ '("\\*scratch\\*" (display-buffer-same-window)))
address@hidden group
address@hidden example
+
+By default, @code{display-buffer-alist} is @code{nil}, so this step is
+skipped.
 
 @item
 Otherwise, if the buffer is already displayed in an existing window,
-reuse that window.  Normally, only windows on the selected frame
-are considered, but windows on other frames are also reusable if you
-change @code{pop-up-frames} (see below) to @code{t}.
+reuse that window.  Normally, only windows on the selected frame are
+considered, but windows on other frames are also reusable if a
+corresponding @code{reusable-frames} action alist entry (@pxref{Buffer
+Display Action Alists,,Action Alists for Buffer Display, elisp, The
+Emacs Lisp Reference Manual}) is used (see the next step for an
+example of how to do that).
 
address@hidden pop-up-frames
 @item
 Otherwise, optionally create a new frame and display the buffer there.
-By default, this step is skipped.  To enable it, change the variable
address@hidden to a address@hidden value.  The special value
address@hidden means to do this only on graphical displays.
+By default, this step is skipped.  To enable it, change the value of
+the option @code{display-buffer-base-action} (@pxref{Choosing
+Window,,Choosing a Window for Displaying a Buffer, elisp, The Emacs
+Lisp Reference Manual}) as follows:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-base-action
+ '((display-buffer-reuse-window display-buffer-pop-up-frame)
+   (reusable-frames . 0)))
address@hidden group
address@hidden example
+
+This customization will also try to make the preceding step search for
+a reusable window on all visible of iconified frames
 
 @item
 Otherwise, try to create a new window by splitting a window on the
@@ -429,9 +454,9 @@ window was not split before (to avoid excessive splitting).
 
 @item
 Otherwise, display the buffer in a window previously showing it.
-Normally, only windows on the selected frame are considered, but if
address@hidden is address@hidden the window may be also on another
-frame.
+Normally, only windows on the selected frame are considered, but with
+a suitable @code{reusable-frames} action alist entry (see above) the
+window may be also on another frame.
 
 @item
 Otherwise, display the buffer in an existing window on the selected
@@ -442,14 +467,9 @@ If all the above methods fail for whatever reason, create 
a new frame
 and display the buffer there.
 @end itemize
 
-A more advanced and flexible way to customize the behavior of
address@hidden is by using the option @code{display-buffer-alist}
-mentioned in the next section.
-
 
 @node Temporary Displays
 @subsection Displaying non-editable buffers.
address@hidden pop-up windows
 @cindex temporary windows
 
 Some buffers are shown in windows for perusal rather than for editing.
@@ -459,24 +479,24 @@ buffer called @file{*Completions*} instead.  Such buffers 
are usually
 displayed only for a short period of time.
 
   Normally, Emacs chooses the window for such temporary displays via
address@hidden as described above.  The @file{*Completions*}
-buffer, on the other hand, is normally displayed in a window at the
-bottom of the selected frame, regardless of the number of windows
-already shown on that frame.
address@hidden as described in the previous subsection.  The
address@hidden buffer, on the other hand, is normally displayed
+in a window at the bottom of the selected frame, regardless of the
+number of windows already shown on that frame.
 
   If you prefer Emacs to display a temporary buffer in a different
 fashion, we recommend customizing the variable
 @code{display-buffer-alist} (@pxref{Choosing Window,,Choosing a Window
-for Display, elisp, The Emacs Lisp Reference Manual}).  For example,
-to display @file{*Completions*} by splitting a window as described in
-the previous section, use the following form in your initialization
-file (@pxref{Init File}):
+for Displaying a Buffer, elisp, The Emacs Lisp Reference Manual}).
+For example, to display @file{*Completions*} always below the selected
+window, use the following form in your initialization file
+(@pxref{Init File}):
 
 @example
 @group
 (customize-set-variable
  'display-buffer-alist
- '(("\\*Completions\\*" display-buffer-pop-up-window)))
+ '(("\\*Completions\\*" display-buffer-below-selected)))
 @end group
 @end example
 
diff --git a/doc/lispref/elisp.texi b/doc/lispref/elisp.texi
index 7dd1e89..05066a2 100644
--- a/doc/lispref/elisp.texi
+++ b/doc/lispref/elisp.texi
@@ -1043,9 +1043,7 @@ Windows
 * Cyclic Window Ordering::  Moving around the existing windows.
 * Buffers and Windows::     Each window displays the contents of a buffer.
 * Switching Buffers::       Higher-level functions for switching to a buffer.
-* Choosing Window::         How to choose a window for displaying a buffer.
-* Display Action Functions:: Subroutines for @code{display-buffer}.
-* Choosing Window Options:: Extra options affecting how buffers are displayed.
+* Displaying Buffers::      Displaying a buffer in a suitable window.
 * Window History::          Each window remembers the buffers displayed in it.
 * Dedicated Windows::       How to avoid displaying another buffer in
                               a specific window.
@@ -1067,6 +1065,18 @@ Windows
                               redisplay going past a certain point,
                               or window configuration changes.
 
+Displaying Buffers
+
+* Choosing Window::         How to choose a window for displaying a buffer.
+* Buffer Display Action Functions:: Support functions for buffer display.
+* Buffer Display Action Alists:: Alists for fine-tuning buffer display
+                              action functions.
+* Choosing Window Options:: Extra options affecting how buffers are displayed.
+* Precedence of Action Functions:: A tutorial explaining the precedence of
+                              buffer display action functions.
+* The Zen of Buffer Display:: How to avoid that buffers get lost in between
+                              windows.
+
 Side Windows
 
 * Displaying Buffers in Side Windows:: An action function for displaying
diff --git a/doc/lispref/frames.texi b/doc/lispref/frames.texi
index 1e008da..e95a684 100644
--- a/doc/lispref/frames.texi
+++ b/doc/lispref/frames.texi
@@ -3198,11 +3198,11 @@ and should be preferred when specifying a address@hidden
 @code{drag-with-mode-line} parameter.
 
   When a child frame is used for displaying a buffer via
address@hidden (@pxref{Display Action Functions}),
-the frame's @code{auto-hide-function} parameter (@pxref{Frame
-Interaction Parameters}) can be set to a function, in order to
-appropriately deal with the frame when the window displaying the buffer
-shall be quit.
address@hidden (@pxref{Buffer Display Action
+Functions}), the frame's @code{auto-hide-function} parameter
+(@pxref{Frame Interaction Parameters}) can be set to a function, in
+order to appropriately deal with the frame when the window displaying
+the buffer shall be quit.
 
   When a child frame is used during minibuffer interaction, for example,
 to display completions in a separate window, the @code{minibuffer-exit}
diff --git a/doc/lispref/windows.texi b/doc/lispref/windows.texi
index 960573d..7f2dff1 100644
--- a/doc/lispref/windows.texi
+++ b/doc/lispref/windows.texi
@@ -25,9 +25,7 @@ is displayed in windows.
 * Cyclic Window Ordering::  Moving around the existing windows.
 * Buffers and Windows::     Each window displays the contents of a buffer.
 * Switching Buffers::       Higher-level functions for switching to a buffer.
-* Choosing Window::         How to choose a window for displaying a buffer.
-* Display Action Functions:: Subroutines for @code{display-buffer}.
-* Choosing Window Options:: Extra options affecting how buffers are displayed.
+* Displaying Buffers::      Displaying a buffer in a suitable window.
 * Window History::          Each window remembers the buffers displayed in it.
 * Dedicated Windows::       How to avoid displaying another buffer in
                               a specific window.
@@ -1542,11 +1540,11 @@ direction as the existing window combination 
(otherwise, a new internal
 window is created anyway).
 
 @item window-size
-This means that @code{display-buffer} makes a new parent window when it
-splits a window and is passed a @code{window-height} or
address@hidden entry in the @var{alist} argument (@pxref{Display
-Action Functions}).  Otherwise, window splitting behaves as for a value
-of @code{nil}.
+This means that @code{display-buffer} makes a new parent window when
+it splits a window and is passed a @code{window-height} or
address@hidden entry in the @var{alist} argument (@pxref{Buffer
+Display Action Functions}).  Otherwise, window splitting behaves as
+for a value of @code{nil}.
 
 @item temp-buffer-resize
 In this case @code{with-temp-buffer-window} makes a new parent window
@@ -1879,7 +1877,7 @@ most recently used one (@pxref{Cyclic Window Ordering}).
 @cindex ordering of windows, cyclic
 @cindex window ordering, cyclic
 
-  When you use the command @kbd{C-x o} (@code{other-window}) to select
+  When you use the command @address@hidden o}} (@code{other-window}) to select
 some other window, it moves through live windows in a specific order.
 For any given configuration of windows, this order never varies.  It
 is called the @dfn{cyclic ordering of windows}.
@@ -1899,7 +1897,7 @@ if omitted or @code{nil}, it defaults to the selected 
window.
 The optional argument @var{minibuf} specifies whether minibuffer windows
 should be included in the cyclic ordering.  Normally, when @var{minibuf}
 is @code{nil}, a minibuffer window is included only if it is currently
-active; this matches the behavior of @kbd{C-x o}.  (Note that a
+active; this matches the behavior of @address@hidden o}}.  (Note that a
 minibuffer window is active as long as its minibuffer is in use; see
 @ref{Minibuffers}).
 
@@ -2083,7 +2081,8 @@ variables in the specified buffer.  However, if the 
optional argument
 @var{keep-margins} is address@hidden, it leaves @var{window}'s display
 margins, fringes and scroll bar settings alone.
 
-When writing an application, you should normally use the higher-level
+When writing an application, you should normally use
address@hidden (@pxref{Choosing Window}) or the higher-level
 functions described in @ref{Switching Buffers}, instead of calling
 @code{set-window-buffer} directly.
 
@@ -2168,7 +2167,6 @@ frame on its terminal, the buffer is replaced anyway.
 @node Switching Buffers
 @section Switching to a Buffer in a Window
 @cindex switching to a buffer
address@hidden displaying a buffer
 
 This section describes high-level functions for switching to a specified
 buffer in some window.  In general, ``switching to a buffer'' means to
@@ -2327,32 +2325,71 @@ unless @var{norecord} is address@hidden
 @end deffn
 
 
address@hidden Displaying Buffers
address@hidden Displaying a Buffer in a Suitable Window
address@hidden buffer display
address@hidden displaying a buffer
+
+This section describes lower-level functions Emacs uses to find or
+create a window for displaying a specified buffer.  The common
+workhorse of these functions is @code{display-buffer} which eventually
+handles all incoming requests for buffer display (@pxref{Choosing
+Window}).
+
+   @code{display-buffer} delegates the task of finding a suitable
+window to so-called action functions (@pxref{Buffer Display Action
+Functions}).  Before, @code{display-buffer} compiles a so-called
+action alist---a special association list action functions can use to
+fine-tune their behavior--- and passes that alist on to each action
+function it calls (@pxref{Buffer Display Action Alists}).
+
+   The behavior of @code{display-buffer} is highly customizable.  To
+understand how customizations are put into practice, readers may want
+to study examples illustrating the precedence acquired by
address@hidden for calling action functions (@pxref{Precedence
+of Action Functions}).  To avoid that Lisp programs calling
address@hidden come into conflict with users customizing its
+behavior, it may make sense to follow a number of guidelines which are
+sketched in the final part of this section (@pxref{The Zen of Buffer
+Display}).
+
address@hidden
+* Choosing Window::         How to choose a window for displaying a buffer.
+* Buffer Display Action Functions:: Support functions for buffer display.
+* Buffer Display Action Alists:: Alists for fine-tuning buffer display.
+* Choosing Window Options:: Extra options affecting how buffers are displayed.
+* Precedence of Action Functions:: Examples to explain the precedence of
+                              action functions.
+* The Zen of Buffer Display:: How to avoid that buffers get lost in between
+                              windows.
address@hidden menu
+
+
 @node Choosing Window
address@hidden Choosing a Window for Display
address@hidden Choosing a Window for Displaying a Buffer
 
-  The command @code{display-buffer} flexibly chooses a window for
+The command @code{display-buffer} flexibly chooses a window for
 display, and displays a specified buffer in that window.  It can be
 called interactively, via the key binding @kbd{C-x 4 C-o}.  It is also
 used as a subroutine by many functions and commands, including
 @code{switch-to-buffer} and @code{pop-to-buffer} (@pxref{Switching
 Buffers}).
 
address@hidden buffer display display action
 @cindex display action
address@hidden action function, for @code{display-buffer}
address@hidden action alist, for @code{display-buffer}
   This command performs several complex steps to find a window to
 display in.  These steps are described by means of @dfn{display
 actions}, which have the form @code{(@var{function} . @var{alist})}.
 Here, @var{function} is either a function or a list of functions,
-which we refer to as @dfn{action functions}; @var{alist} is an
-association list, which we refer to as an @dfn{action alist}.
+which we refer to as ``action functions'' (@pxref{Buffer Display
+Action Functions}); @var{alist} is an association list, which we refer
+to as ``action alist'' (@pxref{Buffer Display Action Alists}).  See
address@hidden Zen of Buffer Display}, for samples of display actions.
 
   An action function accepts two arguments: the buffer to display and
 an action alist.  It attempts to display the buffer in some window,
 picking or creating a window according to its own criteria.  If
 successful, it returns the window; otherwise, it returns @code{nil}.
address@hidden Action Functions}, for a list of predefined action
-functions.
 
   @code{display-buffer} works by combining display actions from
 several sources, and calling the action functions in turn, until one
@@ -2364,11 +2401,13 @@ This command makes @var{buffer-or-name} appear in some 
window, without
 selecting the window or making the buffer current.  The argument
 @var{buffer-or-name} must be a buffer or the name of an existing
 buffer.  The return value is the window chosen to display the buffer.
+It is @code{nil} if no suitable window was found.
 
 The optional argument @var{action}, if address@hidden, should normally
 be a display action (described above).  @code{display-buffer} builds a
 list of action functions and an action alist, by consolidating display
-actions from the following sources (in order):
+actions from the following sources (in order of their precedence,
+highest ranking first):
 
 @itemize
 @item
@@ -2388,24 +2427,49 @@ The constant @code{display-buffer-fallback-action}.
 @end itemize
 
 @noindent
-Each action function is called in turn, passing the buffer as the
-first argument and the combined action alist as the second argument,
-until one of the functions returns address@hidden  The caller can
-pass @code{(allow-no-window . t)} as an element of the action alist to
-indicate its readiness to handle the case of not displaying the
-buffer in a window.
+In practice this means that @code{display-buffer} builds a list of all
+action functions specified by these display actions.  The first
+element of this list is the first action function specified by
address@hidden, if any.  Its last element is
address@hidden last action function
+specified by @code{display-buffer-fallback-action}.  Duplicates are
+not removed from this list---hence one and the same action function
+may be called multiple times during one call of @code{display-buffer}.
+
address@hidden calls the action functions specified by this
+list in turn, passing the buffer as the first argument and the
+combined action alist as the second argument, until one of the
+functions returns address@hidden  See @ref{Precedence of Action
+Functions}, for examples how display actions specified by different
+sources are processed by @code{display-buffer}.
+
+Note that the second argument is always the list of @emph{all} action
+alist entries specified by the sources named above.  Hence, the first
+element of that list is the first action alist entry specified by
address@hidden, if any.  Its last element is
+the last alist entry of @code{display-buffer-base-action}, if any (the
+action alist of @code{display-buffer-fallback-action} is empty).
+
+Note also, that the combined action alist may contain duplicate
+entries and entries for the same key with different values.  As a
+rule, action functions always use the first association of a key they
+find.  Hence, the association an action function uses is not
+necessarily the association provided by the display action that
+specified that action function,
 
 The argument @var{action} can also have a address@hidden, non-list
 value.  This has the special meaning that the buffer should be
 displayed in a window other than the selected one, even if the
 selected window is already displaying it.  If called interactively
-with a prefix argument, @var{action} is @code{t}.
+with a prefix argument, @var{action} is @code{t}.  Lisp programs
+should always supply a list value.
 
 The optional argument @var{frame}, if address@hidden, specifies which
 frames to check when deciding whether the buffer is already displayed.
 It is equivalent to adding an element @code{(reusable-frames
-. @var{frame})} to the action alist of @var{action}.  @xref{Display
-Action Functions}.
+. @var{frame})} to the action alist of @var{action} (@pxref{Buffer
+Display Action Alists}).  The @var{frame} argument is provided for
+compatibility reasons, Lisp programs should not use it.
 @end deffn
 
 @defvar display-buffer-overriding-action
@@ -2418,10 +2482,10 @@ default value is empty, i.e., @code{(nil . nil)}.
 The value of this option is an alist mapping conditions to display
 actions.  Each condition may be either a regular expression matching a
 buffer name or a function that takes two arguments: a buffer name and
-the @var{action} argument passed to @code{display-buffer}.  If the name
-of the buffer passed to @code{display-buffer} either matches a regular
-expression in this alist or the function specified by a condition
-returns address@hidden, then @code{display-buffer} uses the
+the @var{action} argument passed to @code{display-buffer}.  If the
+name of the buffer passed to @code{display-buffer} either matches a
+regular expression in this alist or the function specified by a
+condition returns address@hidden, then @code{display-buffer} uses the
 corresponding display action to display the buffer.
 @end defopt
 
@@ -2437,73 +2501,126 @@ This display action specifies the fallback behavior for
 @end defvr
 
 
address@hidden Display Action Functions
address@hidden Action Functions for @code{display-buffer}
address@hidden Buffer Display Action Functions
address@hidden Action Functions for Buffer Display
address@hidden buffer display action function
address@hidden action function, for buffer display
+
+An @dfn{action function} is a function @code{display-buffer} calls for
+choosing a window to display a buffer.  Action functions take two
+arguments: @var{buffer}, the buffer to display, and @var{alist}, an
+action alist (@pxref{Buffer Display Action Alists}).  They are
+supposed to return a window displaying @var{buffer} if they succeed
+and @code{nil} if they fail.
 
-The following basic action functions are defined in Emacs.  Each of
-these functions takes two arguments: @var{buffer}, the buffer to
-display, and @var{alist}, an action alist.  Each action function
-returns the window if it succeeds, and @code{nil} if it fails.
+   The following basic action functions are defined in Emacs.
 
 @defun display-buffer-same-window buffer alist
 This function tries to display @var{buffer} in the selected window.
 It fails if the selected window is a minibuffer window or is dedicated
 to another buffer (@pxref{Dedicated Windows}).  It also fails if
address@hidden has a address@hidden @code{inhibit-same-window} entry.
address@hidden has a address@hidden @code{inhibit-same-window} entry
+(@pxref{Buffer Display Action Alists}).
 @end defun
 
 @defun display-buffer-reuse-window buffer alist
-This function tries to display @var{buffer} by finding a window
-that is already displaying it.
+This function tries to display @var{buffer} by finding a window that
+is already displaying it.
 
 If @var{alist} has a address@hidden @code{inhibit-same-window} entry,
-the selected window is not eligible for reuse.  If @var{alist}
-contains a @code{reusable-frames} entry, its value determines which
-frames to search for a reusable window:
-
address@hidden @bullet
address@hidden
address@hidden means consider windows on the selected frame.
-(Actually, the last non-minibuffer frame.)
address@hidden
address@hidden means consider windows on all frames.
address@hidden
address@hidden means consider windows on all visible frames.
address@hidden
-0 means consider windows on all visible or iconified frames.
address@hidden
-A frame means consider windows on that frame only.
address@hidden itemize
-
-Note that these meanings differ slightly from those of the
address@hidden argument to @code{next-window} (@pxref{Cyclic Window
-Ordering}).
-
-If @var{alist} contains no @code{reusable-frames} entry, this function
-normally searches just the selected frame; however, if the variable
address@hidden is address@hidden, it searches all frames on the
-current terminal.  @xref{Choosing Window Options}.
+the selected window is not eligible for reuse.  The set of frames to
+search for a window already displaying @var{buffer} can be specified
+with the help of a @code{reusable-frames} action alist entry
+(@pxref{Buffer Display Action Alists}).  If @var{alist} contains no
address@hidden entry, this function searches just the selected
+frame.
 
-If this function chooses a window on another frame, it makes that frame
-visible and, unless @var{alist} contains an @code{inhibit-switch-frame}
-entry (@pxref{Choosing Window Options}), raises that frame if necessary.
+If this function chooses a window on another frame, it makes that
+frame visible and, unless @var{alist} contains an
address@hidden entry (@pxref{Buffer Display Action
+Alists}), raises that frame if necessary.
 @end defun
 
 @defun display-buffer-reuse-mode-window buffer alist
 This function tries to display @var{buffer} by finding a window
 that is displaying a buffer in a given mode.
 
-If @var{alist} contains a @code{mode} entry, its value is a major mode
-(a symbol) or a list of major modes.  If @var{alist} contains no
address@hidden entry, the current major mode of @var{buffer} is used.  A
-window is a candidate if it displays a buffer that derives from one of
-the given modes.
+If @var{alist} contains a @code{mode} entry, its value specifes a
+major mode (a symbol) or a list of major modes.  If @var{alist}
+contains no @code{mode} entry, the current major mode of @var{buffer}
+is used instead.  A window is a candidate if it displays a buffer
+whose mode derives from one of the modes specified thusly.
 
-The behavior is also controlled by entries for
+The behavior is also controlled by @var{alist} entries for
 @code{inhibit-same-window}, @code{reusable-frames} and
address@hidden as is done in the function
address@hidden
address@hidden (@pxref{Buffer Display Action Alists}) as
+is done in the function @code{display-buffer-reuse-window}.
address@hidden defun
 
address@hidden display-buffer-pop-up-window buffer alist
+This function tries to display @var{buffer} by splitting the largest
+or least recently-used window (usually located on the selected frame).
+It actually performs the split by calling the function specified by
address@hidden (@pxref{Choosing Window
+Options}).
+
+The size of the new window can be adjusted by supplying
address@hidden and @code{window-width} entries in @var{alist}
+(@pxref{Buffer Display Action Alists}).  If @var{alist} contains a
address@hidden entry, Emacs will also try to preserve the size
+of the new window during future resize operations (@pxref{Preserving
+Window Sizes}).
+
+This function fails if no window can be split.  More often than not
+this happens because no window is large enough to allow splitting.
+Setting @code{split-height-threshold} or @code{split-width-threshold}
+(@pxref{Choosing Window Options}) to lower values may help in this
+regard.  Spliting also fails when the selected frame has an
address@hidden frame parameter; @pxref{Buffer Parameters}.
address@hidden defun
+
address@hidden display-buffer-in-previous-window buffer alist
+This function tries to display @var{buffer} in a window previously
+showing it.  If @var{alist} has a address@hidden
address@hidden entry, the selected window is not eligible
+for reuse.  If @var{alist} contains a @code{reusable-frames} entry,
+its value determines which frames to search for a suitable window
+(@pxref{Buffer Display Action Alists}).
+
+If @var{alist} has a @code{previous-window} entry and the window
+specified by that entry is live and not dedicated to another buffer,
+that window will be preferred, even if it never showed @var{buffer}
+before.
address@hidden defun
+
address@hidden display-buffer-use-some-window buffer alist
+This function tries to display @var{buffer} by choosing an existing
+window and displaying the buffer in that window.  It can fail if all
+windows are dedicated to another buffer (@pxref{Dedicated Windows}).
address@hidden defun
+
address@hidden display-buffer-below-selected buffer alist
+This function tries to display @var{buffer} in a window below the
+selected window.  If there is a window below the selected one and that
+window already displays @var{buffer}, it reuses that window.
+
+If there is no such window, this function tries to create a new window
+by splitting the selected one and display @var{buffer} there.  It will
+also try to adjust that window's size provided @var{alist} contains a
+suitable @code{window-height} or @code{window-width} entry, see above.
+
+If splitting the selected window fails and there is a non-dedicated
+window below the selected one showing some other buffer, it tries to
+use that window for showing @var{buffer}.
address@hidden defun
+
address@hidden display-buffer-at-bottom buffer alist
+This function tries to display @var{buffer} in a window at the bottom
+of the selected frame.
+
+This either tries to split the window at the bottom of the frame or
+the frame's root window, or to reuse an existing window at the bottom
+of the selected frame.
 @end defun
 
 @defun display-buffer-pop-up-frame buffer alist
@@ -2511,8 +2628,8 @@ This function creates a new frame, and displays the 
buffer in that
 frame's window.  It actually performs the frame creation by calling
 the function specified in @code{pop-up-frame-function}
 (@pxref{Choosing Window Options}).  If @var{alist} contains a
address@hidden entry, the associated value
-is added to the newly created frame's parameters.
address@hidden entry, the associated value is added to
+the newly created frame's parameters.
 @end defun
 
 @defun display-buffer-in-child-frame buffer alist
@@ -2528,20 +2645,21 @@ corresponding entry must be added to @var{alist}.
 The appearance of child frames is largely dependent on the parameters
 provided via @var{alist}.  It is advisable to use at least ratios to
 specify the size (@pxref{Size Parameters}) and the position
-(@pxref{Position Parameters}) of the child frame and to add the
address@hidden in order to make sure that the child frame remains
-visible.  For other parameters that should be considered see @ref{Child
-Frames}.
+(@pxref{Position Parameters}) of the child frame and to add a
address@hidden parameter (@pxref{Frame Interaction Parameters}) in
+order to make sure that the child frame remains visible.  For other
+parameters that should be considered see @ref{Child Frames}.
 @end defun
 
 @defun display-buffer-use-some-frame buffer alist
-This function tries to display @var{buffer} by trying to find a
-frame that meets a predicate (by default any frame other than the
-current frame).
+This function tries to display @var{buffer} by finding a frame that
+meets a predicate (by default any frame other than the selected
+frame).
 
-If this function chooses a window on another frame, it makes that frame
-visible and, unless @var{alist} contains an @code{inhibit-switch-frame}
-entry (@pxref{Choosing Window Options}), raises that frame if necessary.
+If this function chooses a window on another frame, it makes that
+frame visible and, unless @var{alist} contains an
address@hidden entry (@pxref{Buffer Display Action
+Alists}), raises that frame if necessary.
 
 If @var{alist} has a address@hidden @code{frame-predicate} entry, its
 value is a function taking one argument (a frame), returning
@@ -2549,233 +2667,282 @@ address@hidden if the frame is a candidate; this 
function replaces the
 default predicate.
 
 If @var{alist} has a address@hidden @code{inhibit-same-window} entry,
-the selected window is used; thus if the selected frame has a single
-window, it is not used.
+the selected window is not used; thus if the selected frame has a
+single window, it is not used.
 @end defun
 
address@hidden display-buffer-pop-up-window buffer alist
-This function tries to display @var{buffer} by splitting the largest
-or least recently-used window (typically one on the selected frame).
-It actually performs the split by calling the function specified in
address@hidden (@pxref{Choosing Window
-Options}).
address@hidden display-buffer-no-window buffer alist
+If @var{alist} has a address@hidden @code{allow-no-window} entry, then
+this function does not display @var{buffer} and returns the symbol
address@hidden  This constitutes the only exception to the convention
+that an action function returns either @code{nil} or a window showing
address@hidden  If @var{alist} has no such @code{allow-no-window}
+entry, this function returns @code{nil}.
+
+If this function returns @code{fail}, @code{display-buffer} will skip
+the execution of any further display actions and return @code{nil}
+immediately.  If this function returns @code{nil},
address@hidden will continue with the next display action, if
+any.
 
-The size of the new window can be adjusted by supplying
address@hidden and @code{window-width} entries in @var{alist}.  To
-adjust the window's height, use an entry whose @sc{car} is
address@hidden and whose @sc{cdr} is one of:
+It is assumed that when a caller of @code{display-buffer} specifies a
address@hidden @code{allow-no-window} entry, it is also able to handle
+a @code{nil} return value.
address@hidden defun
+
+Two action functions are described in their proper
address@hidden (@pxref{Displaying
+Buffers in Side Windows}) and @code{display-buffer-in-atom-window}
+(@pxref{Atomic Windows}).
+
+
address@hidden Buffer Display Action Alists
address@hidden Action Alists for Buffer Display
address@hidden buffer display action alist
address@hidden action alist for buffer display
+
+An @dfn{action alist} is an association list mapping predefined
+symbols recognized by action functions to values these functions are
+supposed to interpret accordingly.  In each call,
address@hidden constructs a new, possibly empty action alist
+and passes that entire list on to any action function it calls.
+
+   By design, action functions are free in their interpretation of
+action alist entries.  In fact, some entries like
address@hidden or @code{previous-window} have a meaning only
+for one or a few action functions and are ignored by the rest.  Other
+entries, like @code{inhibit-same-window} or @code{window-parameters},
+are supposed to be respected by most action functions including those
+provided by application programs and external packages.
+
+   In the previous subsection we have described in detail how
+individual action functions interpret the action alist entries they
+care about.  Here we give a reference list of all known action alist
+entries according to their symbols, together with their values and
+action functions that recognize them.  Throughout this list, the terms
+``buffer'' will refer to the buffer @code{display-buffer} is supposed
+to display and ``value'' to the entry's value.
+
address@hidden @code
address@hidden address@hidden, a buffer display action alist entry}
address@hidden inhibit-same-window
+If the value is address@hidden, this signals that the selected window
+must not be used for displaying the buffer.  All action functions that
+(re-)use an existing window should respect this entry.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden previous-window
+The value must specify a window that may have displayed the buffer
+previously.  @code{display-buffer-in-previous-window} (@pxref{Buffer
+Display Action Functions}) will give preference to such a window
+provided it is still live and not dedicated to another buffer.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden mode
+The value is either a major mode or a list of major modes.
address@hidden (@pxref{Buffer Display Action
+Functions}) may reuse a window whenever the value specified by this
+entry matches the major mode of that window's buffer.  Other action
+functions ignore such entries.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden frame-predicate
+The value must be a function taking one argument (a frame), supposed
+to return address@hidden if that frame is a candidate for displaying
+the buffer.  This entry is used by
address@hidden (@pxref{Buffer Display Action
+Functions}).
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden reusable-frames
+The value specifies the frame(s) to search for a window that can be
+reused because it already displays the buffer.  It can be set as
+follows:
+
address@hidden @bullet
address@hidden
address@hidden means consider only windows on the selected frame.
+(Actually, the last frame used that is not a minibuffer-only frame.)
address@hidden
address@hidden means consider windows on all frames.
address@hidden
address@hidden means consider windows on all visible frames.
address@hidden
+0 means consider windows on all visible or iconified frames.
address@hidden
+A frame means consider windows on that frame only.
address@hidden itemize
+
+Note that the meaning of @code{nil} differs slightly from that of the
address@hidden argument to @code{next-window} (@pxref{Cyclic Window
+Ordering}).
+
+A major client of this is @code{display-buffer-reuse-window}
+(@pxref{Buffer Display Action Functions}) but all other action
+functions that try to reuse a window are affected as well.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden inhibit-switch-frame
+A address@hidden value prevents another frame from being raised or
+selected, if the window chosen by @code{display-buffer} is displayed
+there.  Primarily affected by this are
address@hidden and
address@hidden (@pxref{Buffer Display Action
+Functions}).  @code{display-buffer-pop-up-frame} should be affected as
+well but there is no guarantee that the window manager will comply.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden window-parameters
+The value specifies an alist of window parameters to give the chosen
+window.  All action functions that choose a window should process this
+entry.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden window-height
+The value specifies whether and how to adjust the height of the chosen
+window and can be provided as follows:
 
 @itemize @bullet
 @item
address@hidden means to leave the height of the new window alone.
address@hidden means to leave the height of the chosen window alone.
 
 @item
-A number specifies the desired height of the new window.  An integer
-specifies the number of lines of the window.  A floating-point
+A number specifies the desired height of the chosen window.  An
+integer specifies the number of lines of the window.  A floating-point
 number gives the fraction of the window's height with respect to the
 height of the frame's root window.
 
 @item
-If the @sc{cdr} specifies a function, that function is called with one
-argument: the new window.  The function is supposed to adjust the
+If the value specifies a function, that function is called with one
+argument---the chosen window.  The function is supposed to adjust the
 height of the window; its return value is ignored.  Suitable functions
 are @code{shrink-window-if-larger-than-buffer} and
 @code{fit-window-to-buffer}, see @ref{Resizing Windows}.
 @end itemize
 
-To adjust the window's width, use an entry whose @sc{car} is
address@hidden and whose @sc{cdr} is one of:
+All action functions that choose a window should process this entry.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden window-width
+This entry is similar to the @code{window-height} entry described
+before but can be used to adjust the chosen window's width instead.
+The value can be one of the following:
 
 @itemize @bullet
 @item
address@hidden means to leave the width of the new window alone.
address@hidden means to leave the width of the chosen window alone.
 
 @item
-A number specifies the desired width of the new window.  An integer
+A number specifies the desired width of the chosen window.  An integer
 specifies the number of columns of the window.  A floating-point
 number gives the fraction of the window's width with respect to the
 width of the frame's root window.
 
 @item
-If the @sc{cdr} specifies a function, that function is called with one
-argument: the new window.  The function is supposed to adjust the width
-of the window; its return value is ignored.
+If the value specifies a function, that function is called with one
+argument---the chosen window.  The function is supposed to adjust the
+width of the window; its return value is ignored.
 @end itemize
 
-If @var{alist} contains a @code{preserve-size} entry, Emacs will try to
-preserve the size of the new window during future resize operations
-(@pxref{Preserving Window Sizes}).  The @sc{cdr} of that entry must be a
-cons cell whose @sc{car}, if address@hidden, means to preserve the width
-of the window and whose @sc{cdr}, if address@hidden, means to preserve
-the height of the window.
-
-This function can fail if no window splitting can be performed for some
-reason (e.g., if the selected frame has an @code{unsplittable} frame
-parameter; @pxref{Buffer Parameters}).
address@hidden defun
-
address@hidden display-buffer-below-selected buffer alist
-This function tries to display @var{buffer} in a window below the
-selected window.  If there is a window below the selected one and that
-window already displays @var{buffer}, it reuses that window.
-
-If there is no such window, this function tries to create a new window
-by splitting the selected one and display @var{buffer} there.  It will
-also adjust that window's size provided @var{alist} contains a suitable
address@hidden or @code{window-width} entry, see above.
-
-If splitting the selected window fails and there is a non-dedicated
-window below the selected one showing some other buffer, it uses that
-window for showing @var{buffer}.
address@hidden defun
-
address@hidden display-buffer-in-previous-window buffer alist
-This function tries to display @var{buffer} in a window previously
-showing it.  If @var{alist} has a address@hidden
address@hidden entry, the selected window is not eligible
-for reuse.  If @var{alist} contains a @code{reusable-frames} entry, its
-value determines which frames to search for a suitable window as with
address@hidden
-
-If @var{alist} has a @code{previous-window} entry, the window
-specified by that entry will override any other window found by the
-methods above, even if that window never showed @var{buffer} before.
address@hidden defun
-
address@hidden display-buffer-at-bottom buffer alist
-This function tries to display @var{buffer} in a window at the bottom
-of the selected frame.
-
-This either splits the window at the bottom of the frame or the
-frame's root window, or reuses an existing window at the bottom of the
-selected frame.
address@hidden defun
-
address@hidden display-buffer-use-some-window buffer alist
-This function tries to display @var{buffer} by choosing an existing
-window and displaying the buffer in that window.  It can fail if all
-windows are dedicated to another buffer (@pxref{Dedicated Windows}).
address@hidden defun
-
address@hidden display-buffer-no-window buffer alist
-If @var{alist} has a address@hidden @code{allow-no-window} entry, then
-this function does not display @code{buffer}.  This allows you to
-override the default action and avoid displaying the buffer.  It is
-assumed that when the caller specifies a address@hidden
address@hidden value it can handle a @code{nil} value returned
-from @code{display-buffer} in this case.
address@hidden defun
-
-If the @var{alist} argument of any of these functions contains a
address@hidden entry, @code{display-buffer} assigns the
-elements of the associated value as window parameters of the chosen
-window.
-
-   To illustrate the use of action functions, consider the following
-example.
-
address@hidden
address@hidden
-(display-buffer
- (get-buffer-create "*foo*")
- '((display-buffer-reuse-window
-    display-buffer-pop-up-window
-    display-buffer-pop-up-frame)
-   (reusable-frames . 0)
-   (window-height . 10) (window-width . 40)))
address@hidden group
address@hidden example
-
address@hidden
-Evaluating the form above will cause @code{display-buffer} to proceed as
-follows: If a buffer called *foo* already appears on a visible or
-iconified frame, it will reuse its window.  Otherwise, it will try to
-pop up a new window or, if that is impossible, a new frame and show the
-buffer there.  If all these steps fail, it will proceed using whatever
address@hidden and
address@hidden prescribe.
-
-   Furthermore, @code{display-buffer} will try to adjust a reused window
-(provided *foo* was put by @code{display-buffer} there before) or a
-popped-up window as follows: If the window is part of a vertical
-combination, it will set its height to ten lines.  Note that if, instead
-of the number 10, we specified the function
address@hidden, @code{display-buffer} would come up with a
-one-line window to fit the empty buffer.  If the window is part of a
-horizontal combination, it sets its width to 40 columns.  Whether a new
-window is vertically or horizontally combined depends on the shape of
-the window split and the values of
address@hidden, @code{split-height-threshold}
-and @code{split-width-threshold} (@pxref{Choosing Window Options}).
-
-   Now suppose we combine this call with a preexisting setup for
address@hidden as follows.
-
address@hidden
address@hidden
-(let ((display-buffer-alist
-       (cons
-        '("\\*foo\\*"
-          (display-buffer-reuse-window display-buffer-below-selected)
-          (reusable-frames)
-          (window-height . 5))
-        display-buffer-alist)))
-  (display-buffer
-   (get-buffer-create "*foo*")
-   '((display-buffer-reuse-window
-      display-buffer-pop-up-window
-      display-buffer-pop-up-frame)
-     (reusable-frames . 0)
-     (window-height . 10) (window-width . 40))))
address@hidden group
address@hidden example
+All action functions that choose a window should process this entry.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden preserve-size
+If address@hidden such an entry tells Emacs to preserve the size of
+the window chosen (@pxref{Preserving Window Sizes}).  The value should
+be either @code{(t . nil)} to preserve the width of the window,
address@hidden(nil . t)} to preserve its height or @code{(t . t)} to preserve
+both, its width and its height.  All action functions that choose a
+window should process this entry.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden pop-up-frame-parameters
+The value specifies an alist of frame parameters to give a new frame,
+if one is created.  @code{display-buffer-pop-up-frame} (@pxref{Buffer
+Display Action Functions}) is its one and only addressee.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden parent-frame
+The value specifies the parent frame to be used when the buffer is
+displayed on a child frame.  This entry is used by
address@hidden (@pxref{Buffer Display Action
+Functions}) only.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden child-frame-parameters
+The value specifies an alist of frame parameters used when the buffer
+is displayed on a child frame.  This entry is used by
address@hidden (@pxref{Buffer Display Action
+Functions}) only.
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden side
+The value denotes the side of the frame or window where a new window
+displaying the buffer shall be created.  This entry is used by
address@hidden to indicate the side of the frame
+where a new side window shall be placed (@pxref{Displaying Buffers in
+Side Windows}).  It is also used by
address@hidden to indicate the side of an
+existing window where the new window shall be located (@pxref{Atomic
+Windows}).
 
address@hidden
-This form will have @code{display-buffer} first try reusing a window
-that shows *foo* on the selected frame.  If there's no such window, it
-will try to split the selected window or, if that is impossible, use the
-window below the selected window.
address@hidden address@hidden, a buffer display action alist entry}
address@hidden slot
+If address@hidden, the value specifies the slot of the side window
+supposed to display the buffer.  This entry is used by
address@hidden only (@pxref{Displaying Buffers
+in Side Windows}).
 
-   If there's no window below the selected one, or the window below the
-selected one is dedicated to its buffer, @code{display-buffer} will
-proceed as described in the previous example.  Note, however, that when
-it tries to adjust the height of any reused or popped-up window, it will
-in any case try to set its number of lines to 5 since that value
-overrides the corresponding specification in the @var{action} argument
-of @code{display-buffer}.
address@hidden address@hidden, a buffer display action alist entry}
address@hidden window
+The value specifies a window that is in some way related to the window
+chosen by @code{display-buffer}.  This entry is currently used by
address@hidden to indicate the window on whose
+side the new window shall be created (@pxref{Atomic Windows}).
+
address@hidden address@hidden, a buffer display action alist entry}
address@hidden allow-no-window
+If the value is address@hidden, @code{display-buffer} does not
+necessarily have to display the buffer and the caller is prepared to
+accept that.  This entry is not intended for user customizations since
+there is no guarantee that an arbitrary caller of
address@hidden will be able to handle the case that no window
+will display the buffer.  @code{display-buffer-no-window}
+(@pxref{Buffer Display Action Functions}) is the only action function
+that cares about this entry.
address@hidden table
 
 
 @node Choosing Window Options
address@hidden Additional Options for Displaying Buffers
address@hidden Additional Options for Displaying Buffers
 
-The behavior of the standard display actions of @code{display-buffer}
-(@pxref{Choosing Window}) can be modified by a variety of user
-options.
+The behavior of buffer display actions (@pxref{Choosing Window}) can
+be further modified by the following user options.
 
 @defopt pop-up-windows
 If the value of this variable is address@hidden, @code{display-buffer}
 is allowed to split an existing window to make a new window for
 displaying in.  This is the default.
 
-This variable is provided mainly for backward compatibility.  It is
+This variable is provided for backward compatibility only.  It is
 obeyed by @code{display-buffer} via a special mechanism in
address@hidden, which only calls the action
-function @code{display-buffer-pop-up-window} (@pxref{Display Action
-Functions}) when the value is @code{nil}.  It is not consulted by
address@hidden itself, which the user may specify
-directly in @code{display-buffer-alist} etc.
address@hidden, which calls the action function
address@hidden (@pxref{Buffer Display Action
+Functions}) when the value of this option is address@hidden  It is
+not consulted by @code{display-buffer-pop-up-window} itself, which the
+user may specify directly in @code{display-buffer-alist} etc.
 @end defopt
 
 @defopt split-window-preferred-function
 This variable specifies a function for splitting a window, in order to
 make a new window for displaying a buffer.  It is used by the
 @code{display-buffer-pop-up-window} action function to actually split
-the window (@pxref{Display Action Functions}).
+the window (@pxref{Buffer Display Action Functions}).
 
-The default value is @code{split-window-sensibly}, which is documented
-below.  The value must be a function that takes one argument, a window,
-and return either a new window (which will be used to display the
-desired buffer) or @code{nil} (which means the splitting failed).
+The value must be a function that takes one argument, a window, and
+return either a new window (which will be used to display the desired
+buffer) or @code{nil} (which means the splitting failed).  The default
+value is @code{split-window-sensibly}, which is documented next.
 @end defopt
 
 @defun split-window-sensibly &optional window
@@ -2797,19 +2964,19 @@ well, this function gives up and returns @code{nil}.
 @end defun
 
 @defopt split-height-threshold
-This variable, used by @code{split-window-sensibly}, specifies whether
-to split the window placing the new window below.  If it is an
+This variable specifies whether @code{split-window-sensibly} is
+allowed to split the window placing the new window below.  If it is an
 integer, that means to split only if the original window has at least
 that many lines.  If it is @code{nil}, that means not to split this
 way.
 @end defopt
 
 @defopt split-width-threshold
-This variable, used by @code{split-window-sensibly}, specifies whether
-to split the window placing the new window to the right.  If the value
-is an integer, that means to split only if the original window has at
-least that many columns.  If the value is @code{nil}, that means not
-to split this way.
+This variable specifies whether @code{split-window-sensibly} is
+allowed to split the window placing the new window to the right.  If
+the value is an integer, that means to split only if the original
+window has at least that many columns.  If the value is @code{nil},
+that means not to split this way.
 @end defopt
 
 @defopt even-window-sizes
@@ -2839,9 +3006,9 @@ search any visible or iconified frame, not just the 
selected frame.
 This variable is provided mainly for backward compatibility.  It is
 obeyed by @code{display-buffer} via a special mechanism in
 @code{display-buffer-fallback-action}, which calls the action function
address@hidden (@pxref{Display Action Functions})
-if the value is address@hidden  (This is done before attempting to
-split a window.)  This variable is not consulted by
address@hidden (@pxref{Buffer Display Action
+Functions}) if the value is address@hidden  (This is done before
+attempting to split a window.)  This variable is not consulted by
 @code{display-buffer-pop-up-frame} itself, which the user may specify
 directly in @code{display-buffer-alist} etc.
 @end defopt
@@ -2849,8 +3016,8 @@ directly in @code{display-buffer-alist} etc.
 @defopt pop-up-frame-function
 This variable specifies a function for creating a new frame, in order
 to make a new window for displaying a buffer.  It is used by the
address@hidden action function (@pxref{Display
-Action Functions}).
address@hidden action function (@pxref{Buffer
+Display Action Functions}).
 
 The value should be a function that takes no arguments and returns a
 frame, or @code{nil} if no frame could be created.  The default value
@@ -2860,30 +3027,670 @@ is a function that creates a frame using the 
parameters specified by
 
 @defopt pop-up-frame-alist
 This variable holds an alist of frame parameters (@pxref{Frame
-Parameters}), which is used by the default function in
+Parameters}), which is used by the function specified by
 @code{pop-up-frame-function} to make a new frame.  The default is
 @code{nil}.
address@hidden defopt
 
address@hidden same-window-buffer-names
-A list of buffer names for buffers that should be displayed in the
-selected window.  If a buffer's name is in this list,
address@hidden handles the buffer by showing it in the selected
-window.
+This option is provided for backward compatibility only.  Note, that
+when @code{display-buffer-pop-up-frame} (@pxref{Buffer Display Action
+Functions}) calls the function specified by
address@hidden, it prepends the value of all
address@hidden action alist entries to
address@hidden so that the values specified by the action
+alist entry effectively override any corresponding values of
address@hidden
+
+Hence, users should set up a @code{pop-up-frame-parameters} action
+alist entry in @code{display-buffer-alist} instead of customizing
address@hidden  Only this will guarantee that the value of
+a parameter specified by the user overrides the value of that
+parameter specified by the caller of @code{display-buffer}.
 @end defopt
 
address@hidden same-window-regexps
-A list of regular expressions that specify buffers that should be
-displayed in the selected window.  If the buffer's name matches any of
-the regular expressions in this list, @code{display-buffer} handles the
-buffer by showing it in the selected window.
address@hidden defopt
+   Many efforts in the design of @code{display-buffer} have been given
+to maintain compatibility with code that uses older options like
address@hidden, @code{pop-up-frames},
address@hidden, @code{same-window-buffer-names} and
address@hidden  Lisp Programs and users should refrain
+from using these options.  Above we already warned against customizing
address@hidden  Here we describe how to convert the
+remaining options to use display actions instead.
+
address@hidden @code
address@hidden pop-up-windows
address@hidden address@hidden, replacement for}
+This variable is @code{t} by default.  Instead of customizing it to
address@hidden and thus telling @code{display-buffer} what not to do, it's
+much better to list in @code{display-buffer-base-action} the action
+functions it should try instead as, for example:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-base-action
+ '((display-buffer-reuse-window display-buffer-same-window
+    display-buffer-in-previous-window
+    display-buffer-use-some-window)))
address@hidden group
address@hidden example
+
address@hidden pop-up-frames
address@hidden address@hidden, replacement for}
+Instead of customizing this variable to @code{t}, customize
address@hidden, for example, as follows:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-base-action
+ '((display-buffer-reuse-window display-buffer-pop-up-frame)
+   (reusable-frames . 0)))
address@hidden group
address@hidden example
+
address@hidden same-window-buffer-names
address@hidden same-window-regexps
address@hidden address@hidden, replacement for}
address@hidden address@hidden, replacement for}
+Instead of adding a buffer name or a regular expression to one of
+these options use a @code{display-buffer-alist} entry for that buffer
+specifying the action function @code{display-buffer-same-window}.
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-alist
+ (cons '("\\*foo\\*" (display-buffer-same-window))
+        display-buffer-alist))
address@hidden group
address@hidden example
address@hidden table
+
+
address@hidden Precedence of Action Functions
address@hidden Precedence of Action Functions
address@hidden precedence of buffer display action functions
address@hidden execution order of buffer display action functions
+
+From the past subsections we already know that @code{display-buffer}
+must be supplied with a number of display actions (@pxref{Choosing
+Window}) in order to display a buffer.  In a completely uncustomized
+Emacs, these actions are specified by
address@hidden in the following order of
+precedence: Reuse a window, pop up a new window on the same frame, use
+a window previously showing the buffer, use some window and pop up a
+new frame.  (Note that the remaining actions named by
address@hidden are void in an uncustomized
+Emacs).
+
+Consider the following form:
+
address@hidden
+(display-buffer (get-buffer-create "*foo*"))
address@hidden example
+
address@hidden
+Evaluating this form in the buffer @file{*scratch*} of an uncustomized
+Emacs session will usually fail to reuse a window that shows
address@hidden already but succeed in popping up a new window.
+Evaluating the same form again will now not cause any visible
address@hidden reused the window already showing
address@hidden because that action was applicable and had the highest
+precedence among all applicable actions.
+
+   Popping up a new window will fail if there is not enough space on
+the selected frame.  In an uncustomized Emacs it typically fails when
+there are already two windows on a frame.  For example, if you now
+type @address@hidden 1}} followed by @address@hidden 2}} and evaluate the form
+once more, @file{*foo*} should show up in the lower
address@hidden just used ``some'' window.  If, before
+typing @address@hidden 2}} you had typed @address@hidden o}}, @file{*foo*}
+would have been shown in the upper window because ``some'' window
+stands for the ``least recently used'' window and the selected window
+has been least recently used if and only if it is alone on its frame.
+
+   Let's assume you did not type @address@hidden o}} and @file{*foo*} is
+shown in the lower window.  Type @address@hidden o}} to get there followed
+by @address@hidden left}} and evaluate the form again.  This should
+display @file{*foo*} in the same, lower window because that window had
+already shown @file{*foo*} previously and was therefore chosen instead
+of some other window.
+
+  So far we have only observed the default behavior in an uncustomized
+Emacs session.  To see how this behavior can be customized let's
+consider the option @code{display-buffer-base-action}.  It provides a
+very coarse customization which conceptually affects the display of
address@hidden buffer.  It can be used to supplement the actions supplied
+by @code{display-buffer-fallback-action} by reordering them or by
+adding actions that are not present there but fit more closely the
+user's editing practice.  It can be, however, also used to change the
+default behavior in a more profound way.
+
+   Let's consider a user who, as a rule, prefers to display buffers on
+another frame.  Such a user might provide the following customization:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-base-action
+ '((display-buffer-reuse-window display-buffer-pop-up-frame)
+   (reusable-frames . 0)))
address@hidden group
address@hidden example
+
address@hidden
+This setting will address@hidden to first try to find a
+window showing the buffer on a visible or iconified frame and, if no
+such frame exists, pop up a new frame.  You can observe this behavior
+on a graphical system by typing @address@hidden 1}} in the window showing
address@hidden and evaluating our canonical @code{display-buffer}
+form.  This will usually create (and give focus to) a new frame whose
+root window shows @file{*foo*}.  Iconify that frame and evaluate the
+canonical form again: @code{display-buffer} will reuse the window on
+the new frame (usually raising the frame and giving it focus too).
+
+   Only if creating a new frame fails, @code{display-buffer} will
+apply the actions supplied by @code{display-buffer-fallback-action}
+which means to again try to reuse a window, pop up a new window and so
+on.  A trivial way to make frame creation fail is supplied by the
+following form:
+
address@hidden
address@hidden
+(let ((pop-up-frame-function 'ignore))
+  (display-buffer (get-buffer-create "*foo*")))
address@hidden group
address@hidden example
+
address@hidden
+We will forget about that form immediately after observing that it
+fails to create a new frame and uses a fallback action instead.
+
+   Note that @code{display-buffer-reuse-window} appears redundant in
+the customization of @code{display-buffer-base-action} because it is
+already part of @code{display-buffer-fallback-action} and should be
+tried there anyway.  However, that would fail because due to the
+precedence of @code{display-buffer-base-action} over
address@hidden, at that time
address@hidden would have already won the race.
+In fact
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-base-action
+ '(display-buffer-pop-up-frame (reusable-frames . 0)))
address@hidden group
address@hidden example
+
address@hidden
+would cause @code{display-buffer} to @emph{always} pop up a new frame
+which is probably not what our user wants.
+
+   So far, we have only shown how @emph{users} can customize the
+default behavior of @code{display-buffer}.  Let us now see how
address@hidden can change the course of @code{display-buffer}.
+The canonical way to do that is to use the @var{action} argument of
address@hidden or a function that calls it like, for example,
address@hidden (@pxref{Switching Buffers}).
+
+   Suppose an application wants to display @file{*foo*} preferably
+below the selected window (to immediately attract the attention of the
+user to the new window) or, if that fails, in a window at the bottom
+of the frame.  It could do that with a call like
+
address@hidden
address@hidden
+(display-buffer
+ (get-buffer-create "*foo*")
+ '((display-buffer-below-selected display-buffer-at-bottom)))
address@hidden group
address@hidden example
+
address@hidden
+In order to see how this new, modified form works, delete any frame
+showing @file{*foo*}, type @address@hidden 1}} followed by @address@hidden 2}} 
in the
+window showing @file{*scratch*} and subsequently evaluate that form.
address@hidden should split the upper window and show
address@hidden in the new window.  Alternatively, if after @address@hidden 2}}
+you had typed @address@hidden o}}, @code{display-buffer} would have split the
+window at the bottom instead.
+
+   Suppose now that, before evaluating the new form, you have made the
+selected window as small as possible, for example, by evaluating the
+form @code{(fit-window-to-buffer)} in that window.  In that case,
address@hidden would have failed to split the selected window
+and would have split the frame's root window instead, effectively
+displaying @file{*foo*} at the bottom of the frame.
+
+   In either case, evaluating the new form a second time should reuse
+the window already showing @file{*foo*} since both functions supplied
+by the @var{action} argument try to reuse such a window first.
+
+   By setting the @var{action} argument, an application effectively
+overrules any customization of @code{display-buffer-base-action}.  Our
+user can now either accept the choice of the application or redouble
+by customizing the option @code{display-buffer-alist} as follows:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-alist
+ '(("\\*foo\\*"
+    (display-buffer-reuse-window display-buffer-pop-up-frame))))
address@hidden group
address@hidden example
+
address@hidden
+Trying this with the new, modified form above in a configuration that
+does not show @file{*foo*} anywhere, will display @file{*foo*} on a
+separate frame, completely ignoring the @var{action} argument of
address@hidden
+
+   Note that we didn't care to specify a @code{reusable-frames} action
+alist entry in our specification of @code{display-buffer-alist}.
address@hidden always takes the first one it finds---in our
+case the one specified by @code{display-buffer-base-action}.  If we
+wanted to use a different specification, for example, to exclude
+iconified frames showing @file{*foo*} from the list of reusable ones,
+we would have to specify that separately, however:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-alist
+ '(("\\*foo\\*"
+    (display-buffer-reuse-window display-buffer-pop-up-frame)
+    (reusable-frames . visible))))
address@hidden group
address@hidden example
+
address@hidden
+If you try this, you will notice that repeated attempts to display
address@hidden will succeed to reuse a frame only if that frame is
+visible.
+
+   The above example would allow the conclusion that users customize
address@hidden for the sole purpose to overrule the
address@hidden argument chosen by applications.  Such a conclusion would
+be incorrect.  @code{display-buffer-alist} is the standard option for
+users to direct the course of display of specific buffers in a
+preferred way regardless of whether the display is also guided by an
address@hidden argument.
+
+   We can, however, reasonably conclude that customizing
address@hidden differs from customizing
address@hidden in two major aspects: It is stronger
+because it overrides the @var{action} argument of
address@hidden  And it allows to explicitly specify the
+affected buffers.  In fact, displaying other buffers is not affected
+in any way by a customization for @file{*foo*}.  For example,
+
address@hidden
+(display-buffer (get-buffer-create "*bar*"))
address@hidden example
+
address@hidden
+continues being governed by the settings of
address@hidden and
address@hidden only.
+
+   We could stop with our examples here but Lisp programs still have
+an ace up their sleeves which they can use to overrule any
+customization of @code{display-buffer-alist}.  It's the variable
address@hidden which they can bind around
address@hidden calls as follows:
+
address@hidden
address@hidden
+(let ((display-buffer-overriding-action
+       '((display-buffer-same-window))))
+  (display-buffer
+   (get-buffer-create "*foo*")
+   '((display-buffer-below-selected display-buffer-at-bottom))))
address@hidden group
address@hidden example
+
address@hidden
+Evaluating this form will usually display @file{*foo*} in the selected
+window regardless of the @var{action} argument and any user
+customizations.  (Usually, an application will not bother to also
+provide an @var{action} argument.  Here it just serves to illustrate
+the fact that it gets overridden.)
+
+It might be illustrative to look at the list of action functions
address@hidden would have tried to display @file{*foo*} with
+the customizations we provided here.  The list (including comments
+explaining who added this and the subsequent elements) is:
+
address@hidden
address@hidden
+(display-buffer-same-window  ;; `display-buffer-overriding-action'
+ display-buffer-reuse-window ;; `display-buffer-alist'
+ display-buffer-pop-up-frame
+ display-buffer-below-selected ;; ACTION argument
+ display-buffer-at-bottom
+ display-buffer-reuse-window ;; `display-buffer-base-action'
+ display-buffer-pop-up-frame
+ display-buffer--maybe-same-window ;; `display-buffer-fallback-action'
+ display-buffer-reuse-window
+ display-buffer--maybe-pop-up-frame-or-window
+ display-buffer-in-previous-window
+ display-buffer-use-some-window
+ display-buffer-pop-up-frame)
address@hidden group
address@hidden example
+
address@hidden
+Note that among the internal functions listed here
address@hidden is effectively ignored while
address@hidden actually runs
address@hidden
+
+The action alist passed in each function call is:
+
address@hidden
address@hidden
+((reusable-frames . visible)
+ (reusable-frames . 0))
address@hidden group
address@hidden example
+
address@hidden
+which shows that we have used the second specification of
address@hidden above overriding the specification
+supplied by @code{display-buffer-base-action}.  Suppose our user had
+written that as
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-alist
+ '(("\\*foo\\*"
+    (display-buffer-reuse-window display-buffer-pop-up-frame)
+    (inhibit-same-window . t)
+    (reusable-frames . visible))))
address@hidden group
address@hidden example
+
address@hidden
+In this case the @code{inhibit-same-window} alist entry will
+successfully invalidate the @code{display-buffer-same-window}
+specification from @code{display-buffer-overriding-action} and
address@hidden will show @file{*foo*} on another frame.  To
+make @code{display-buffer-overriding-action} more robust in this
+regard, the application would have to specify an appropriate
address@hidden entry too, for example, as follows:
+
address@hidden
address@hidden
+(let ((display-buffer-overriding-action
+       '(display-buffer-same-window (inhibit-same-window . nil))))
+  (display-buffer (get-buffer-create "*foo*")))
address@hidden group
address@hidden example
+
address@hidden
+This last example shows that while the precedence order of action
+functions is fixed as described in @ref{Choosing Window}, an action
+alist entry specified by a display action ranked lower in that order
+can affect the execution of a higher ranked display action.
+
+
address@hidden The Zen of Buffer Display
address@hidden The Zen of Buffer Display
address@hidden guidelines for buffer display
address@hidden writing buffer display actions
address@hidden buffer display conventions
+
+In its most simplistic form, a frame accommodates always one single
+window that can be used for displaying a buffer.  As a consequence, it
+is always the latest call of @code{display-buffer} that will have
+succeeded in placing its buffer there.
+
+   Since working with such a frame is not very practical, Emacs by
+default allows for more complex frame layouts controlled by the
+default values of the frame size and the @code{split-height-threshold}
+and @code{split-width-threshold} options.  Displaying a buffer not yet
+shown on a frame then either splits the single window on that frame or
+(re-)uses one of its two windows.
+
+   The default behavior is abandoned as soon as the user customizes
+one of these thresholds or manually changes the frame's layout.  The
+default behavior is also abandoned when calling @code{display-buffer}
+with a address@hidden @var{action} argument or the user customizes one
+of the options mentioned in the previous subsections.  Mastering
address@hidden soon may become a frustrating experience due to
+the plethora of applicable display actions and the resulting frame
+layouts.
+
+   However, refraining from using buffer display functions and falling
+back on a split & delete windows metaphor is not a good idea either.
+Buffer display functions give Lisp programs and users a framework to
+reconcile their different needs; no comparable framework exists for
+splitting and deleting windows.  They also allow to at least partially
+restore the layout of a frame when removing a buffer from it later
+(@pxref{Quitting Windows}).
+
+   Below we will give a number of guidelines to redeem the frustration
+mentioned above and thus to avoid that buffers literally get lost in
+between the windows of a frame.
+
address@hidden @asis
address@hidden Write display actions without stress
+Writing display actions can be a pain because one has to lump together
+action functions and action alists in one huge list.  (Historical
+reasons prevented us from having @code{display-buffer} support
+separate arguments for these.)  It might help to memorize some basic
+forms like the ones listed below:
+
address@hidden
+'(nil (inhibit-same-window . t))
address@hidden example
+
address@hidden
+specifies an action alist entry only and no action function.  Its sole
+purpose is to inhibit a @code{display-buffer-same-window} function
+specified elsewhere from showing the buffer in the same window, see
+also the last example of the preceding subsection.
+
address@hidden
+'(display-buffer-below-selected)
address@hidden example
+
address@hidden
+on the other hand specifies one action function and an empty action
+alist.  To combine the effects of the above two specifications one
+would write the form
+
address@hidden
+'(display-buffer-below-selected (inhibit-same-window . t))
address@hidden example
+
address@hidden
+to add another action function one would write
+
address@hidden
address@hidden
+'((display-buffer-below-selected display-buffer-at-bottom)
+  (inhibit-same-window . t))
address@hidden group
address@hidden example
+
address@hidden
+and to add another alist entry one would write
+
address@hidden
address@hidden
+'((display-buffer-below-selected display-buffer-at-bottom)
+  (inhibit-same-window . t)
+  (window-height . fit-window-to-buffer))
address@hidden group
address@hidden example
+
address@hidden
+That last form can be used as @var{action} argument of
address@hidden in the following way:
+
address@hidden
address@hidden
+(display-buffer
+ (get-buffer-create "*foo*")
+ '((display-buffer-below-selected display-buffer-at-bottom)
+   (inhibit-same-window . t)
+   (window-height . fit-window-to-buffer)))
address@hidden group
address@hidden example
+
address@hidden
+In a customization of @code{display-buffer-alist} it would be used as
+follows:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-alist
+ '(("\\*foo\\*"
+    (display-buffer-below-selected display-buffer-at-bottom)
+    (inhibit-same-window . t)
+    (window-height . fit-window-to-buffer))))
address@hidden group
address@hidden example
+
address@hidden
+To add a customization for a second buffer one would then write:
+
address@hidden
address@hidden
+(customize-set-variable
+ 'display-buffer-alist
+ '(("\\*foo\\*"
+    (display-buffer-below-selected display-buffer-at-bottom)
+    (inhibit-same-window . t)
+    (window-height . fit-window-to-buffer))
+   ("\\*bar\\*"
+    (display-buffer-reuse-window display-buffer-pop-up-frame)
+    (reusable-frames . visible))))
address@hidden group
address@hidden example
+
address@hidden Treat each other with respect
address@hidden and @code{display-buffer-base-action} are
+user options---Lisp programs must never set or rebind them.
address@hidden, on the other hand, is
+reserved for applications---who seldom use that option and if they use
+it, then with utmost care.
+
+   Older implementations of @code{display-buffer} frequently caused
+users and applications to fight over the settings of user options like
address@hidden and @code{pop-up-windows} (@pxref{Choosing Window
+Options}).  This was one major reason for redesigning
address@hidden provide a clear framework specifying what
+users and applications should be allowed to do.
+
+   Lisp Programs must be prepared that a user's customizations may
+cause buffers to get displayed in an unexpected way.  They should
+never assume in their subsequent behavior, that the buffer has been
+shown precisely the way they asked for in the @var{action} argument of
address@hidden
+
+   Users should not pose too many and too severe restrictions on how
+arbitrary buffers get displayed.  Otherwise, they will risk to lose
+the characteristics of showing a buffer for a certain purpose.
+Suppose an lisp program has been written to compare different versions
+of a buffer in two windows side-by-side.  If the customization of
address@hidden prescribes that any such buffer should be
+always shown in or below the selected window, the lisp program will
+have a hard time to set up the desired window configuration via
address@hidden
+
+   To specify a preference for showing an arbitrary buffer, users
+should customize @code{display-buffer-base-action}.  An example of how
+users who prefer working with multiple frames would do that was given
+in the previous subsection.  @code{display-buffer-alist} should be
+reserved for displaying specific buffers in a specific way.
+
address@hidden Consider reusing a window that already shows the buffer
+Generally, it's always a good idea for users and lisp program
+programmers to be prepared for the case that a window already shows
+the buffer in question and to reuse that window.  In the preceding
+subsection we have shown that failing to do so properly may cause
address@hidden to continuously pop up a new frame although a
+frame showing that buffer existed already.  In a few cases only, it
+might be undesirable to reuse a window, for example, when a different
+portion of the buffer should be shown in that window.
+
+   Hence, @code{display-buffer-reuse-window} is one action function
+that should be used as often as possible, both in @var{action}
+arguments and customizations.  An @code{inhibit-same-window} entry in
+the @var{action} argument usually takes care of the most common case
+where reusing a window showing the buffer should be avoided---that
+where the window in question is the selected one.
+
address@hidden Attract focus to the window chosen
+This is a no-brainer for people working with multiple frames---the
+frame showing the buffer will automatically raise and get focus unless
+an @code{inhibit-switch-frame} entry forbids it.  For single frame
+users this task can be considerably more difficult.  In particular,
address@hidden and
address@hidden can become obtrusive in this
+regard.  They split or use a seemingly arbitrary (often the largest or
+least recently used) window, distracting the user's attention.
+
+Some Lisp programs therefore try to choose a window at the bottom of
+the frame, for example, in order to display the buffer in vicinity of
+the minibuffer window where the user is expected to answer a question
+related to the new window.  For non-input related actions
address@hidden might be preferable because the
+selected window usually already has the user's attention.
+
address@hidden Handle subsequent invocations of @code{display-buffer}
address@hidden is not overly well suited for displaying several
+buffers in sequence and making sure that all these buffers are shown
+orderly in the resulting window configuration.  Again, the standard
+action functions @code{display-buffer-pop-up-window} and
address@hidden are not very suited for this
+purpose due to their somewhat chaotic nature in more complex
+configurations.
+
+   To produce a window configuration displaying multiple buffers (or
+different views of one and the same buffer) in one and the same
+display cycle, lisp program programmers will unavoidably have to write
+their own action functions.  A few tricks listed below might help in
+this regard.
+
address@hidden @bullet
address@hidden
+Making windows atomic (@pxref{Atomic Windows}) avoids that an
+existing window composition gets broken when popping up a new window.
+The new window will pop up outside the composition instead.
+
address@hidden
+Temporarily dedicating windows to their buffers (@pxref{Dedicated
+Windows}) avoids that a window gets used for displaying a different
+buffer.  A non-dedicated window will be used instead.
+
address@hidden
+Calling @code{window-preserve-size} (@pxref{Preserving Window Sizes})
+will try to keep the size of the argument window unchanged when
+popping up a new window.  You have to make sure that another window in
+the same combination can be shrunk instead, though.
+
address@hidden
+Side windows (@pxref{Side Windows}) can be used for displaying
+specific buffers always in a window at the same position of a frame.
+This permits to group buffers that do not compete for being shown at
+the same time on a frame and show any such buffer in the same window
+without disrupting the display of other buffers.
+
address@hidden
+Child frames (@pxref{Child Frames}) can be used to display a buffer
+within the screen estate of the selected frame without disrupting that
+frame's window configuration and without the overhead associated with
+full-fledged frames as inflicted by @code{display-buffer-pop-up-frame}.
address@hidden itemize
address@hidden table
 
address@hidden same-window-p buffer-name
-This function returns @code{t} if displaying a buffer
-named @var{buffer-name} with @code{display-buffer} would
-put it in the selected window.
address@hidden defun
 
 @node Window History
 @section Window History
@@ -3202,12 +4009,13 @@ main window is either a ``normal'' live window or 
specifies the area
 containing all the normal windows.
 
    In their most simple form of use, side windows allow to display
-specific buffers always in the same area of a frame.  Hence they can be
-regarded as a generalization of the concept provided by
address@hidden (@pxref{Display Action Functions}) to
-the remaining sides of a frame.  With suitable customizations, however,
-side windows can be also used to provide frame layouts similar to those
-found in so-called integrated development environments (IDEs).
+specific buffers always in the same area of a frame.  Hence they can
+be regarded as a generalization of the concept provided by
address@hidden (@pxref{Buffer Display Action
+Functions}) to the remaining sides of a frame.  With suitable
+customizations, however, side windows can be also used to provide
+frame layouts similar to those found in so-called integrated
+development environments (IDEs).
 
 @menu
 * Displaying Buffers in Side Windows:: An action function for displaying
@@ -3221,9 +4029,9 @@ found in so-called integrated development environments 
(IDEs).
 @node Displaying Buffers in Side Windows
 @subsection Displaying Buffers in Side Windows
 
-The following action function for @code{display-buffer} (@pxref{Display
-Action Functions}) creates or reuses a side window for displaying the
-specified buffer.
+The following action function for @code{display-buffer} (@pxref{Buffer
+Display Action Functions}) creates or reuses a side window for
+displaying the specified buffer.
 
 @defun display-buffer-in-side-window buffer alist
 This function displays @var{buffer} in a side window of the selected
@@ -3263,11 +4071,11 @@ explicitly provided via a @code{window-parameters} 
entry in @var{alist}.
 @end defun
 
 By default, side windows cannot be split via @code{split-window}
-(@pxref{Splitting Windows}).  Also, a side window is not reused or split
-by any buffer display action (@pxref{Display Action Functions}) unless
-it is explicitly specified as target of that action.  Note also that
address@hidden cannot make a side window the only window on
-its frame (@pxref{Deleting Windows}).
+(@pxref{Splitting Windows}).  Also, a side window is not reused or
+split by any buffer display action (@pxref{Buffer Display Action
+Functions}) unless it is explicitly specified as target of that
+action.  Note also that @code{delete-other-windows} cannot make a side
+window the only window on its frame (@pxref{Deleting Windows}).
 
    Once set up, side windows also change the behavior of the commands
 @code{switch-to-prev-buffer} and @code{switch-to-next-buffer}
@@ -3453,9 +4261,9 @@ retain their respective sizes when maximizing the frame, 
the variable
 @xref{Resizing Windows}.
 
    The last form also makes sure that none of the created side windows
-are accessible via @kbd{C-x o} by installing the @code{no-other-window}
+are accessible via @address@hidden o}} by installing the @code{no-other-window}
 parameter for each of these windows.  In addition, it makes sure that
-side windows are not deleted via @kbd{C-x 1} by installing the
+side windows are not deleted via @address@hidden 1}} by installing the
 @code{no-delete-other-windows} parameter for each of these windows.
 
    Since @code{dired} buffers have no fixed names, we use a special
@@ -3547,7 +4355,7 @@ does is to set the @code{window-atom} parameter of each 
descendant of
 
 To create a new atomic window from an existing live window or to add a
 new window to an existing atomic window, the following buffer display
-action function (@pxref{Display Action Functions}) can be used:
+action function (@pxref{Buffer Display Action Functions}) can be used:
 
 @defun display-buffer-in-atom-window buffer alist
 This function tries to display @var{buffer} in a new window that will be