Fix bogus crash with -DENABLE_CHECKING.

[emacs.git] / man / frames.texi

@c This is part of the Emacs manual.
@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 1999, 2000,
@c   2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Frames, International, Windows, Top
@chapter Frames and Graphical Displays
@cindex frames

  When using a graphical display, you can create multiple windows at
the system in a single Emacs session.  Each system-level window that
belongs to Emacs displays a @dfn{frame} which can contain one or
several Emacs windows.  A frame initially contains a single
general-purpose Emacs window which you can subdivide vertically or
horizontally into smaller windows.  A frame normally contains its own
echo area and minibuffer, but you can make frames that don't have
these---they use the echo area and minibuffer of another frame.

  To avoid confusion, we reserve the word ``window'' for the
subdivisions that Emacs implements, and never use it to refer to a
frame.

  Editing you do in one frame affects the other frames.  For
instance, if you put text in the kill ring in one frame, you can yank it
in another frame.  If you exit Emacs through @kbd{C-x C-c} in one frame,
it terminates all the frames.  To delete just one frame, use @kbd{C-x 5
0} (that is zero, not @kbd{o}).

  Emacs compiled for MS-DOS emulates some windowing functionality,
so that you can use many of the features described in this chapter.
@xref{MS-DOS Mouse}, for more information.

@menu
* Mouse Commands::      Moving, cutting, and pasting, with the mouse.
* Secondary Selection:: Cutting without altering point and mark.
* Clipboard::           Using the clipboard for selections.
* Mouse References::    Using the mouse to select an item from a list.
* Menu Mouse Clicks::   Mouse clicks that bring up menus.
* Mode Line Mouse::     Mouse clicks on the mode line.
* Creating Frames::     Creating additional Emacs frames with various contents.
* Frame Commands::      Iconifying, deleting, and switching frames.
* Speedbar::            How to make and use a speedbar frame.
* Multiple Displays::   How one Emacs job can talk to several displays.
* Special Buffer Frames::  You can make certain buffers have their own frames.
* Frame Parameters::    Changing the colors and other modes of frames.
* Scroll Bars::         How to enable and disable scroll bars; how to use them.
* Wheeled Mice::        Using mouse wheels for scrolling.
* Drag and Drop::       Using drag and drop to open files and insert text.
* Menu Bars::           Enabling and disabling the menu bar.
* Tool Bars::           Enabling and disabling the tool bar.
* Dialog Boxes::        Controlling use of dialog boxes.
* Tooltips::            Displaying information at the current mouse position.
* Mouse Avoidance::     Moving the mouse pointer out of the way.
* Non-Window Terminals::  Multiple frames on terminals that show only one.
* XTerm Mouse::         Using the mouse in an XTerm terminal emulator.
@end menu

@node Mouse Commands
@section Mouse Commands for Editing
@cindex mouse buttons (what they do)

  The mouse commands for selecting and copying a region are mostly
compatible with the @code{xterm} program.  You can use the same mouse
commands for copying between Emacs and other window-based programs.
Most of these commands also work in Emacs when you run it under an
@code{xterm} terminal.

@kindex DELETE @r{(and mouse selection)}
  If you select a region with any of these mouse commands, and then
immediately afterward type the @key{DELETE} function key, it deletes the
region that you selected.  The @key{BACKSPACE} function key and the
@acronym{ASCII} character @key{DEL} do not do this; if you type any other key
in between the mouse command and @key{DELETE}, it does not do this.

@findex mouse-set-region
@findex mouse-set-point
@findex mouse-yank-at-click
@findex mouse-save-then-click
@kindex Mouse-1
@kindex Mouse-2
@kindex Mouse-3
@table @kbd
@item Mouse-1
Move point to where you click (@code{mouse-set-point}).
This is normally the left button.

@vindex x-mouse-click-focus-ignore-position
Normally, Emacs does not distinguish between ordinary mouse clicks and
clicks that select a frame.  When you click on a frame to select it,
that also changes the selected window and cursor position according to
the mouse click position.  On the X window system, you can change this
behavior by setting the variable
@code{x-mouse-click-focus-ignore-position} to @code{t}.  Then the
first click selects the frame, but does not affect the selected window
or cursor position.  If you click again in the same place, since that
click will be in the selected frame, it will change the window or
cursor position.

@item Drag-Mouse-1
Set the region to the text you select by dragging, and copy it to the
kill ring (@code{mouse-set-region}).  You can specify both ends of the
region with this single command.

@vindex mouse-scroll-min-lines
If you move the mouse off the top or bottom of the window while
dragging, the window scrolls at a steady rate until you move the mouse
back into the window.  This way, you can select regions that don't fit
entirely on the screen.  The number of lines scrolled per step depends
on how far away from the window edge the mouse has gone; the variable
@code{mouse-scroll-min-lines} specifies a minimum step size.

@vindex mouse-drag-copy-region
If the variable @code{mouse-drag-copy-region} is @code{nil}, this
mouse command does not copy the selected region into the kill ring.

@item Mouse-2
Yank the last killed text, where you click (@code{mouse-yank-at-click}).
This is normally the middle button.

@item Mouse-3
This command, @code{mouse-save-then-kill}, has several functions
depending on where you click and the status of the region.

The most basic case is when you click @kbd{Mouse-1} in one place and
then @kbd{Mouse-3} in another.  This selects the text between those two
positions as the region.  It also copies the new region to the kill
ring, so that you can copy it to someplace else.

If you click @kbd{Mouse-1} in the text, scroll with the scroll bar, and
then click @kbd{Mouse-3}, it remembers where point was before scrolling
(where you put it with @kbd{Mouse-1}), and uses that position as the
other end of the region.  This is so that you can select a region that
doesn't fit entirely on the screen.

More generally, if you do not have a highlighted region, @kbd{Mouse-3}
selects the text between point and the click position as the region.  It
does this by setting the mark where point was, and moving point to where
you click.

If you have a highlighted region, or if the region was set just before
by dragging button 1, @kbd{Mouse-3} adjusts the nearer end of the region
by moving it to where you click.  The adjusted region's text also
replaces the old region's text in the kill ring.

If you originally specified the region using a double or triple
@kbd{Mouse-1}, so that the region is defined to consist of entire words
or lines, then adjusting the region with @kbd{Mouse-3} also proceeds by
entire words or lines.

If you use @kbd{Mouse-3} a second time consecutively, at the same place,
that kills the region already selected.

@item Double-Mouse-1
This key sets the region around the word which you click on.  If you
click on a character with ``symbol'' syntax (such as underscore, in C
mode), it sets the region around the symbol surrounding that character.

If you click on a character with open-parenthesis or close-parenthesis
syntax, it sets the region around the parenthetical grouping
which that character starts or ends.  If you click on a character with
string-delimiter syntax (such as a singlequote or doublequote in C), it
sets the region around the string constant (using heuristics to figure
out whether that character is the beginning or the end of it).

@item Double-Drag-Mouse-1
This key selects a region made up of the words you drag across.

@item Triple-Mouse-1
This key sets the region around the line you click on.

@item Triple-Drag-Mouse-1
This key selects a region made up of the lines you drag across.
@end table

  The simplest way to kill text with the mouse is to press @kbd{Mouse-1}
at one end, then press @kbd{Mouse-3} twice at the other end.
@xref{Killing}.  To copy the text into the kill ring without deleting it
from the buffer, press @kbd{Mouse-3} just once---or just drag across the
text with @kbd{Mouse-1}.  Then you can copy it elsewhere by yanking it.

@vindex mouse-yank-at-point
  To yank the killed or copied text somewhere else, move the mouse there
and press @kbd{Mouse-2}.  @xref{Yanking}.  However, if
@code{mouse-yank-at-point} is non-@code{nil}, @kbd{Mouse-2} yanks at
point.  Then it does not matter where you click, or even which of the
frame's windows you click on.  The default value is @code{nil}.  This
variable also affects yanking the secondary selection.

@cindex cutting
@cindex pasting
@cindex X cutting and pasting
  To copy text to another windowing application, kill it or save it in
the kill ring.  Then use the ``paste'' or ``yank'' command of the
other application to insert the text.

  To copy text from another windowing application, use its ``cut'' or
``copy'' command to select the text you want.  Then yank it in Emacs
with @kbd{C-y} or @kbd{Mouse-2}.

@cindex primary selection
@cindex cut buffer
@cindex selection, primary
@vindex x-cut-buffer-max
  When Emacs puts text into the kill ring, or rotates text to the
front of the kill ring, it sets the @dfn{primary selection} in the
window system.  This is how other windowing applications can access
the text.  On the X Window System, emacs also stores the text in the
cut buffer, but only if the text is short enough (the value of
@code{x-cut-buffer-max} specifies the maximum number of characters);
putting long strings in the cut buffer can be slow.

  The commands to yank the first entry in the kill ring actually check
first for a primary selection in another program; after that, they check
for text in the cut buffer.  If neither of those sources provides text
to yank, the kill ring contents are used.

  The standard coding system for X Window System selections is
@code{compound-text-with-extensions}.  To specify another coding
system for selections, use @kbd{C-x @key{RET} x} or @kbd{C-x @key{RET}
X}.  @xref{Communication Coding}.

@node Secondary Selection
@section Secondary Selection
@cindex secondary selection

  The @dfn{secondary selection} is another way of selecting text using
the X Window System.  It does not use point or the mark, so you can
use it to kill text without setting point or the mark.

@table @kbd
@findex mouse-set-secondary
@kindex M-Drag-Mouse-1
@item M-Drag-Mouse-1
Set the secondary selection, with one end at the place where you press
down the button, and the other end at the place where you release it
(@code{mouse-set-secondary}).  The highlighting appears and changes as
you drag.  You can control the appearance of the highlighting by
customizing the @code{secondary-selection} face (@pxref{Face
Customization}).

If you move the mouse off the top or bottom of the window while
dragging, the window scrolls at a steady rate until you move the mouse
back into the window.  This way, you can mark regions that don't fit
entirely on the screen.

This way of setting the secondary selection does not alter the kill ring.

@findex mouse-start-secondary
@kindex M-Mouse-1
@item M-Mouse-1
Set one endpoint for the @dfn{secondary selection}
(@code{mouse-start-secondary}).

@findex mouse-secondary-save-then-kill
@kindex M-Mouse-3
@item M-Mouse-3
Make a secondary selection, using the place specified with @kbd{M-Mouse-1}
as the other end (@code{mouse-secondary-save-then-kill}).  This also
puts the selected text in the kill ring.  A second click at the same
place kills the secondary selection just made.

@findex mouse-yank-secondary
@kindex M-Mouse-2
@item M-Mouse-2
Insert the secondary selection where you click
(@code{mouse-yank-secondary}).  This places point at the end of the
yanked text.
@end table

Double or triple clicking of @kbd{M-Mouse-1} operates on words and
lines, much like @kbd{Mouse-1}.

If @code{mouse-yank-at-point} is non-@code{nil}, @kbd{M-Mouse-2}
yanks at point.  Then it does not matter precisely where you click; all
that matters is which window you click on.  @xref{Mouse Commands}.

@node Clipboard
@section Using the Clipboard
@cindex clipboard
@vindex x-select-enable-clipboard
@findex menu-bar-enable-clipboard
@cindex OpenWindows
@cindex Gnome

  Apart from the primary and secondary selection types, Emacs can
handle the @dfn{clipboard} selection type which is used by some
applications, particularly under OpenWindows and Gnome.

  The command @kbd{M-x menu-bar-enable-clipboard} makes the @code{Cut},
@code{Paste} and @code{Copy} menu items, as well as the keys of the same
names, all use the clipboard.

  You can customize the variable @code{x-select-enable-clipboard} to make
the Emacs yank functions consult the clipboard before the primary
selection, and to make the kill functions to store in the clipboard as
well as the primary selection.  Otherwise they do not access the
clipboard at all.  Using the clipboard is the default on MS-Windows and Mac,
but not on other systems.

@node Mouse References
@section Following References with the Mouse
@kindex Mouse-1 @r{(selection)}
@kindex Mouse-2 @r{(selection)}

  Some read-only Emacs buffers include references you can follow, or
commands you can activate.  These include names of files, of buffers,
of possible completions, of matches for a pattern, as well as the
buttons in Help buffers and customization buffers.  You can follow the
reference or activate the command by moving point to it and typing
@key{RET}.  You can also do this with the mouse, using either
@kbd{Mouse-1} or @kbd{Mouse-2}.

  Since yanking text into a read-only buffer is not allowed, these
buffers generally define @kbd{Mouse-2} to follow a reference or
activate a command.  For example, if you click @kbd{Mouse-2} on a file
name in a Dired buffer, you visit that file.  If you click
@kbd{Mouse-2} on an error message in the @samp{*Compilation*} buffer,
you go to the source code for that error message.  If you click
@kbd{Mouse-2} on a completion in the @samp{*Completions*} buffer, you
choose that completion.

  However, most applications use @kbd{Mouse-1} to do this sort of
thing, so Emacs implements this too.  If you click @kbd{Mouse-1}
quickly on a reference or button, it follows or activates.  If you
click slowly, it moves point as usual.  Dragging, meaning moving the
mouse while it is held down, also has its usual behavior of setting
the region.

@vindex mouse-1-click-in-non-selected-windows
  Normally, the @kbd{Mouse-1} click behavior is performed on links in
any window.  The variable @code{mouse-1-click-in-non-selected-windows}
controls whether @kbd{Mouse-1} has this behavior even in non-selected
windows, or only in the selected window.

@vindex mouse-highlight
  You can usually tell when @kbd{Mouse-1} and @kbd{Mouse-2} have this
special sort of meaning because the sensitive text highlights when you
move the mouse over it.  The variable @code{mouse-highlight} controls
whether to do this highlighting always (even when such text appears
where the mouse already is), never, or only immediately after you move
the mouse.

@vindex mouse-1-click-follows-link
  In Emacs versions before 22, only @kbd{Mouse-2} follows links and
@kbd{Mouse-1} always sets point.  If you prefer this older behavior,
set the variable @code{mouse-1-click-follows-link} to @code{nil}.
This variable also lets you choose various other alternatives for
following links with the mouse.  Type @kbd{C-h v
mouse-1-click-follows-link @key{RET}} for more details.

@node Menu Mouse Clicks
@section Mouse Clicks for Menus

  Several mouse clicks with the @key{CTRL} and @key{SHIFT} modifiers
bring up menus.

@table @kbd
@item C-Mouse-1
@kindex C-Mouse-1
This menu is for selecting a buffer.

The MSB (``mouse select buffer'') global minor mode makes this
menu smarter and more customizable.  @xref{Buffer Menus}.

@item C-Mouse-2
@kindex C-Mouse-2
This menu is for specifying faces and other text properties
for editing formatted text.  @xref{Formatted Text}.

@item C-Mouse-3
@kindex C-Mouse-3
This menu is mode-specific.  For most modes if Menu-bar mode is on,
this menu has the same items as all the mode-specific menu-bar menus
put together.  Some modes may specify a different menu for this
button.@footnote{Some systems use @kbd{Mouse-3} for a mode-specific
menu.  We took a survey of users, and found they preferred to keep
@kbd{Mouse-3} for selecting and killing regions.  Hence the decision
to use @kbd{C-Mouse-3} for this menu.  To use @kbd{Mouse-3} instead,
do @code{(global-set-key [mouse-3] 'mouse-popup-menubar-stuff)}.}  If
Menu-bar mode is off, this menu contains all the items which would be
present in the menu bar---not just the mode-specific ones---so that
you can access them without having to display the menu bar.

@item S-Mouse-1
This menu is for specifying the frame's default font.
@end table

@node Mode Line Mouse
@section Mode Line Mouse Commands
@cindex mode line, mouse
@cindex mouse on mode line

  You can use mouse clicks on window mode lines to select and manipulate
windows.

  Some areas of the mode line, such as the buffer name and the major
mode name, have their own special mouse bindings.  These areas are
highlighted when you hold the mouse over them, and information about
the special bindings will be displayed (@pxref{Tooltips}).  This
section's commands do not apply in those areas.

@table @kbd
@item Mouse-1
@kindex Mouse-1 @r{(mode line)}
@kbd{Mouse-1} on a mode line selects the window it belongs to.  By
dragging @kbd{Mouse-1} on the mode line, you can move it, thus
changing the height of the windows above and below.  Changing heights
with the mouse in this way never deletes windows, it just refuses to
make any window smaller than the minimum height.

@item Mouse-2
@kindex Mouse-2 @r{(mode line)}
@kbd{Mouse-2} on a mode line expands that window to fill its frame.

@item Mouse-3
@kindex Mouse-3 @r{(mode line)}
@kbd{Mouse-3} on a mode line deletes the window it belongs to.  If the
frame has only one window, it buries the current buffer instead, and
switches to another buffer.

@item C-Mouse-2
@kindex C-mouse-2 @r{(mode line)}
@kbd{C-Mouse-2} on a mode line splits the window above
horizontally, above the place in the mode line where you click.
@end table

@kindex C-Mouse-2 @r{(scroll bar)}
@kindex Mouse-1 @r{(scroll bar)}
  Using @kbd{Mouse-1} on the divider between two side-by-side mode
lines, you can move the vertical boundary left or right.  Using
@kbd{C-Mouse-2} on a scroll bar splits the corresponding window
vertically.  @xref{Split Window}.

@node Creating Frames
@section Creating Frames
@cindex creating frames

@kindex C-x 5
  The prefix key @kbd{C-x 5} is analogous to @kbd{C-x 4}, with parallel
subcommands.  The difference is that @kbd{C-x 5} commands create a new
frame rather than just a new window in the selected frame (@pxref{Pop
Up Window}).  If an existing visible or iconified frame already displays
the requested material, these commands use the existing frame, after
raising or deiconifying as necessary.

  The various @kbd{C-x 5} commands differ in how they find or create the
buffer to select:

@table @kbd
@item C-x 5 2
@kindex C-x 5 2
@findex make-frame-command
Create a new frame (@code{make-frame-command}).
@item C-x 5 b @var{bufname} @key{RET}
Select buffer @var{bufname} in another frame.  This runs
@code{switch-to-buffer-other-frame}.
@item C-x 5 f @var{filename} @key{RET}
Visit file @var{filename} and select its buffer in another frame.  This
runs @code{find-file-other-frame}.  @xref{Visiting}.
@item C-x 5 d @var{directory} @key{RET}
Select a Dired buffer for directory @var{directory} in another frame.
This runs @code{dired-other-frame}.  @xref{Dired}.
@item C-x 5 m
Start composing a mail message in another frame.  This runs
@code{mail-other-frame}.  It is the other-frame variant of @kbd{C-x m}.
@xref{Sending Mail}.
@item C-x 5 .
Find a tag in the current tag table in another frame.  This runs
@code{find-tag-other-frame}, the multiple-frame variant of @kbd{M-.}.
@xref{Tags}.
@item C-x 5 r @var{filename} @key{RET}
@kindex C-x 5 r
@findex find-file-read-only-other-frame
Visit file @var{filename} read-only, and select its buffer in another
frame.  This runs @code{find-file-read-only-other-frame}.
@xref{Visiting}.
@end table

@cindex default-frame-alist
@cindex initial-frame-alist
  You can control the appearance of new frames you create by setting the
frame parameters in @code{default-frame-alist}.  You can use the
variable @code{initial-frame-alist} to specify parameters that affect
only the initial frame.  @xref{Initial Parameters,,, elisp, The Emacs
Lisp Reference Manual}, for more information.

@cindex font (default)
  The easiest way to specify the principal font for all your Emacs
frames is with an X resource (@pxref{Font X}), but you can also do it by
modifying @code{default-frame-alist} to specify the @code{font}
parameter, as shown here:

@example
(add-to-list 'default-frame-alist '(font . "10x20"))
@end example

@noindent
Here's a similar example for specifying a foreground color:

@example
(add-to-list 'default-frame-alist '(foreground-color . "blue"))
@end example

@node Frame Commands
@section Frame Commands

  The following commands let you create, delete and operate on frames:

@table @kbd
@item C-z
@kindex C-z @r{(X windows)}
@findex iconify-or-deiconify-frame
Iconify the selected Emacs frame (@code{iconify-or-deiconify-frame}).
The normal meaning of @kbd{C-z}, to suspend Emacs, is not useful under
a graphical display that allows multiple applications to operate
simultaneously in their own windies, so Emacs gives @kbd{C-z} a
different binding in that case.

If you type this command on an Emacs frame's icon, it deiconifies the frame.

@item C-x 5 0
@kindex C-x 5 0
@findex delete-frame
Delete the selected frame (@code{delete-frame}).  This is not allowed if
there is only one frame.

@item C-x 5 o
@kindex C-x 5 o
@findex other-frame
Select another frame, raise it, and warp the mouse to it so that it
stays selected.  If you repeat this command, it cycles through all the
frames on your terminal.

@item C-x 5 1
@kindex C-x 5 1
@findex delete-other-frames
Delete all frames except the selected one.
@end table

@vindex focus-follows-mouse
  To make the command @kbd{C-x 5 o} work properly, you must tell Emacs
how the system (or the window manager) generally handles
focus-switching between windows.  There are two possibilities: either
simply moving the mouse onto a window selects it (gives it focus), or
you have to click on it in a suitable way to do so.  Unfortunately
there is no way Emacs can find out automatically which way the system
handles this, so you have to explicitly say, by setting the variable
@code{focus-follows-mouse}.  If just moving the mouse onto a window
selects it, that variable should be @code{t}; if a click is necessary,
the variable should be @code{nil}.

@node Speedbar
@section Speedbar Frames
@cindex speedbar

@cindex attached frame (of speedbar)
  The @dfn{speedbar} is a special frame for conveniently navigating in
or operating on another frame.  The speedbar, when it exists, is
always associated with a specific frame, called its @dfn{attached
frame}; all speedbar operations act on that frame.

  Type @kbd{M-x speedbar} to create the speedbar and associate it with
the current frame.  To dismiss the speedbar, type @kbd{M-x speedbar}
again, or select the speedbar and type @kbd{q}.  (You can also delete
the speedbar frame like any other Emacs frame.)  If you wish to
associate the speedbar with a different frame, dismiss it and call
@kbd{M-x speedbar} from that frame.

  The speedbar can operate in various modes.  Its default mode is
@dfn{File Display} mode, which shows the files in the current
directory of the selected window of the attached frame, one file per
line.  Clicking on a file name visits that file in the selected window
of the attached frame, and clicking on a directory name shows that
directory in the speedbar (@pxref{Mouse References}).  Each line also
has a box, @samp{[+]} or @samp{<+>}, that you can click on to
@dfn{expand} the contents of that item.  Expanding a directory adds
the contents of that directory to the speedbar display, underneath the
directory's own line.  Expanding an ordinary file adds a list of the
tags in that file to the speedbar display; you can click on a tag name
to jump to that tag in the selected window of the attached frame.
When a file or directory is expanded, the @samp{[+]} changes to
@samp{[-]}; you can click on that box to @dfn{contract} the item,
hiding its contents.

  You navigate through the speedbar using the keyboard, too.  Typing
@kbd{RET} while point is on a line in the speedbar is equivalent to
clicking the item on the current line, and @kbd{SPC} expands or
contracts the item.  @kbd{U} displays the parent directory of the
current directory.  To copy, delete, or rename the file on the current
line, type @kbd{C}, @kbd{D}, and @kbd{R} respectively.  To create a
new directory, type @kbd{M}.

  Another general-purpose speedbar mode is @dfn{Buffer Display} mode;
in this mode, the speedbar displays a list of Emacs buffers.  To
switch to this mode, type @kbd{b} in the speedbar.  To return to File
Display mode, type @kbd{f}.  You can also change the display mode by
clicking @kbd{mouse-3} anywhere in the speedbar window (or
@kbd{mouse-1} on the mode-line) and selecting @samp{Displays} in the
pop-up menu.

  Some major modes, including Rmail mode, Info, and GUD, have
specialized ways of putting useful items into the speedbar for you to
select.  For example, in Rmail mode, the speedbar shows a list of Rmail
files, and lets you move the current message to another Rmail file by
clicking on its @samp{<M>} box.

  For more details on using and programming the speedbar, @xref{Top,
Speedbar,,speedbar, Speedbar Manual}.

@node Multiple Displays
@section Multiple Displays
@cindex multiple displays

  A single Emacs can talk to more than one X display.  Initially, Emacs
uses just one display---the one specified with the @env{DISPLAY}
environment variable or with the @samp{--display} option (@pxref{Initial
Options}).  To connect to another display, use the command
@code{make-frame-on-display}:

@findex make-frame-on-display
@table @kbd
@item M-x make-frame-on-display @key{RET} @var{display} @key{RET}
Create a new frame on display @var{display}.
@end table

  A single X server can handle more than one screen.  When you open
frames on two screens belonging to one server, Emacs knows they share a
single keyboard, and it treats all the commands arriving from these
screens as a single stream of input.

  When you open frames on different X servers, Emacs makes a separate
input stream for each server.  This way, two users can type
simultaneously on the two displays, and Emacs will not garble their
input.  Each server also has its own selected frame.  The commands you
enter with a particular X server apply to that server's selected frame.

  Despite these features, people using the same Emacs job from different
displays can still interfere with each other if they are not careful.
For example, if any one types @kbd{C-x C-c}, that exits the Emacs job
for all of them!

@node Special Buffer Frames
@section Special Buffer Frames

@vindex special-display-buffer-names
  You can make certain chosen buffers, which Emacs normally displays
in ``another window,'' appear in special frames of their own.  To do
this, set the variable @code{special-display-buffer-names} to a list
of buffer names; any buffer whose name is in that list automatically
gets a special frame, when an Emacs command wants to display it ``in
another window.''

  For example, if you set the variable this way,

@example
(setq special-display-buffer-names
      '("*Completions*" "*grep*" "*tex-shell*"))
@end example

@noindent
then completion lists, @code{grep} output and the @TeX{} mode shell
buffer get individual frames of their own.  These frames, and the
windows in them, are never automatically split or reused for any other
buffers.  They continue to show the buffers they were created for,
unless you alter them by hand.  Killing the special buffer deletes its
frame automatically.

@vindex special-display-regexps
  More generally, you can set @code{special-display-regexps} to a list
of regular expressions; then a buffer gets its own frame if its name
matches any of those regular expressions.  (Once again, this applies only
to buffers that normally get displayed for you in ``another window.'')

@vindex special-display-frame-alist
  The variable @code{special-display-frame-alist} specifies the frame
parameters for these frames.  It has a default value, so you don't need
to set it.

  For those who know Lisp, an element of
@code{special-display-buffer-names} or @code{special-display-regexps}
can also be a list.  Then the first element is the buffer name or
regular expression; the rest of the list specifies how to create the
frame.  It can be an association list specifying frame parameter
values; these values take precedence over parameter values specified
in @code{special-display-frame-alist}.  If you specify the symbol
@code{same-window} as a ``frame parameter'' in this list, with a
non-@code{nil} value, that means to use the selected window if
possible.  If you use the symbol @code{same-frame} as a ``frame
parameter'' in this list, with a non-@code{nil} value, that means to
use the selected frame if possible.

  Alternatively, the value can have this form:

@example
(@var{function} @var{args}...)
@end example

@noindent
where @var{function} is a symbol.  Then the frame is constructed by
calling @var{function}; its first argument is the buffer, and its
remaining arguments are @var{args}.

   An analogous feature lets you specify buffers which should be
displayed in the selected window.  @xref{Force Same Window}.  The
same-window feature takes precedence over the special-frame feature;
therefore, if you add a buffer name to
@code{special-display-buffer-names} and it has no effect, check to see
whether that feature is also in use for the same buffer name.

@node Frame Parameters
@section Setting Frame Parameters
@cindex Auto-Raise mode
@cindex Auto-Lower mode

@kindex S-Mouse-1
  You can specify the font and colors used for text display, and the
colors for the frame borders, the cursor, and the mouse cursor, by
customizing the faces @code{default}, @code{border}, @code{cursor} and
@code{mouse}.  @xref{Face Customization}.  You can also set a frame's
default font through a pop-up menu.  Press @kbd{S-Mouse-1} to activate
this menu.

  These commands are available for controlling the window management
behavior of the selected frame.

@table @kbd
@findex auto-raise-mode
@item M-x auto-raise-mode
Toggle whether or not the selected frame should auto-raise.  Auto-raise
means that every time you move the mouse onto the frame, it raises the
frame.

Some window managers also implement auto-raise.  If you enable
auto-raise for Emacs frames in your window manager, it will work, but
it is beyond Emacs' control, so @code{auto-raise-mode} has no effect
on it.

@findex auto-lower-mode
@item M-x auto-lower-mode
Toggle whether or not the selected frame should auto-lower.
Auto-lower means that every time you move the mouse off the frame,
the frame moves to the bottom of the stack on the screen.

The command @code{auto-lower-mode} has no effect on auto-lower
implemented by the window manager.  To control that, you must use the
appropriate window manager features.
@end table

  In Emacs versions that use an X toolkit, the color-setting and
font-setting functions don't affect menus and the menu bar, since they
are displayed by their own widget classes.  To change the appearance of
the menus and menu bar, you must use X resources (@pxref{Resources}).
@xref{Colors}, regarding colors.  @xref{Font X}, regarding choice of
font.

  Colors, fonts, and other attributes of the frame's display can also
be customized by setting frame parameters in the variable
@code{default-frame-alist} (@pxref{Creating Frames}).  For a detailed
description of frame parameters and customization, see @ref{Frame
Parameters,,, elisp, The Emacs Lisp Reference Manual}.

@node Scroll Bars
@section Scroll Bars
@cindex Scroll Bar mode
@cindex mode, Scroll Bar

  On graphical displays, Emacs normally makes a @dfn{scroll bar} at
the left of each Emacs window.@footnote{Placing it at the left is
usually more useful with overlapping frames with text starting at the
left margin.}  The scroll bar runs the height of the window, and shows
a moving rectangular inner box which represents the portion of the
buffer currently displayed.  The entire height of the scroll bar
represents the entire length of the buffer.

  You can use @kbd{Mouse-2} (normally, the middle button) in the scroll
bar to move or drag the inner box up and down.  If you move it to the
top of the scroll bar, you see the top of the buffer.  If you move it to
the bottom of the scroll bar, you see the bottom of the buffer.

  The left and right buttons in the scroll bar scroll by controlled
increments.  @kbd{Mouse-1} (normally, the left button) moves the line at
the level where you click up to the top of the window.  @kbd{Mouse-3}
(normally, the right button) moves the line at the top of the window
down to the level where you click.  By clicking repeatedly in the same
place, you can scroll by the same distance over and over.

  You can also click @kbd{C-Mouse-2} in the scroll bar to split a
window vertically.  The split occurs on the line where you click.

@findex scroll-bar-mode
@vindex scroll-bar-mode
  You can enable or disable Scroll Bar mode with the command @kbd{M-x
scroll-bar-mode}.  With no argument, it toggles the use of scroll
bars.  With an argument, it turns use of scroll bars on if and only if
the argument is positive.  This command applies to all frames,
including frames yet to be created.  Customize the variable
@code{scroll-bar-mode} to control the use of scroll bars at startup.
You can use it to specify that they are placed at the right of windows
if you prefer that.  You have to set this variable through the
@samp{Customize} interface (@pxref{Easy Customization}), or it will
not work properly.

  You can also use the X resource @samp{verticalScrollBars} to control
the initial setting of Scroll Bar mode.  @xref{Resources}.

@findex toggle-scroll-bar
  To enable or disable scroll bars for just the selected frame, use the
command @kbd{M-x toggle-scroll-bar}.

@vindex scroll-bar-width
@cindex width of the scroll bar
  You can control the scroll bar width by changing the value of the
@code{scroll-bar-width} frame parameter.

@node Wheeled Mice
@section Scrolling With ``Wheeled'' Mice

@cindex mouse wheel
@cindex wheel, mouse
@findex mouse-wheel-mode
@cindex Mouse Wheel minor mode
@cindex mode, Mouse Wheel
  Some mice have a ``wheel'' instead of a third button.  You can
usually click the wheel to act as either @kbd{Mouse-2} or
@kbd{Mouse-3}, depending on the setup.  You can also use the wheel to
scroll windows instead of using the scroll bar or keyboard commands.
Mouse wheel support only works if the system generates appropriate
events; whenever possible, it is turned on by default.  To toggle this
feature, use @kbd{M-x mouse-wheel-mode}.

@vindex mouse-wheel-follow-mouse
@vindex mouse-wheel-scroll-amount
@vindex mouse-wheel-progressive-speed
  The variables @code{mouse-wheel-follow-mouse} and
@code{mouse-wheel-scroll-amount} determine where and by how much
buffers are scrolled.  The variable
@code{mouse-wheel-progressive-speed} determines whether the scroll
speed is linked to how fast you move the wheel.

@node Drag and Drop
@section Drag and Drop
@cindex drag and drop

  Emacs supports @dfn{drag and drop} using the mouse.  For instance,
dropping text onto an Emacs frame inserts the text where it is dropped.
Dropping a file onto an Emacs frame visits that file.  As a special
case, dropping the file on a Dired buffer moves or copies the file
(according to the conventions of the application it came from) into the
directory displayed in that buffer.

@vindex dnd-open-file-other-window
  Dropping a file normally visits it in the window you drop it on.  If
you prefer to visit the file in a new window in such cases, customize
the variable @code{dnd-open-file-other-window}.

  The XDND and Motif drag and drop protocols, and the old KDE 1.x
protocol, are currently supported.

@node Menu Bars
@section Menu Bars
@cindex Menu Bar mode
@cindex mode, Menu Bar

  You can turn display of menu bars on or off with @kbd{M-x
menu-bar-mode} or by customizing the variable @code{menu-bar-mode}.
With no argument, this command toggles Menu Bar mode, a
minor mode.  With an argument, the command turns Menu Bar mode on if the
argument is positive, off if the argument is not positive.  You can use
the X resource @samp{menuBarLines} to control the initial setting of
Menu Bar mode.  @xref{Resources}.

@kindex C-Mouse-3 @r{(when menu bar is disabled)}
  Expert users often turn off the menu bar, especially on text-only
terminals, where this makes one additional line available for text.
If the menu bar is off, you can still pop up a menu of its contents
with @kbd{C-Mouse-3} on a display which supports pop-up menus.
@xref{Menu Mouse Clicks}.

  @xref{Menu Bar}, for information on how to invoke commands with the
menu bar.  @xref{X Resources}, for how to customize the menu bar
menus' visual appearance.

@node Tool Bars
@section Tool Bars
@cindex Tool Bar mode
@cindex mode, Tool Bar
@cindex icons, toolbar

  The @dfn{tool bar} is a line (or lines) of icons at the top of the
Emacs window, just below the menu bar.  You can click on these icons
with the mouse to do various jobs.

  The global tool bar contains general commands.  Some major modes
define their own tool bars to replace it.  A few ``special'' modes
that are not designed for ordinary editing remove some items from the
global tool bar.

  Tool bars work only on a graphical display.  The tool bar uses colored
XPM icons if Emacs was built with XPM support.  Otherwise, the tool
bar uses monochrome icons (PBM or XBM format).

  You can turn display of tool bars on or off with @kbd{M-x
tool-bar-mode} or by customizing the option @code{tool-bar-mode}.

@node Dialog Boxes
@section Using Dialog Boxes
@cindex dialog boxes

@vindex use-dialog-box
  A dialog box is a special kind of menu for asking you a yes-or-no
question or some other special question.  Many Emacs commands use a
dialog box to ask a yes-or-no question, if you used the mouse to
invoke the command to begin with.

  You can customize the variable @code{use-dialog-box} to suppress the
use of dialog boxes.  This also controls whether to use file selection
windows (but those are not supported on all platforms).

@vindex use-file-dialog
  A file selection window is a special kind of dialog box for asking
for file names.  You can customize the variable @code{use-file-dialog}
to suppress the use of file selection windows, even if you still want
other kinds of dialogs.  This variable has no effect if you have
suppressed all dialog boxes with the variable @code{use-dialog-box}.

@vindex x-gtk-show-hidden-files
  For Gtk+ version 2.4 and newer, Emacs use the Gtk+ file chooser
dialog.  Emacs adds a toggle button that enables and disables showing
of hidden files (files starting with a dot) in that dialog.  The
variable @code{x-gtk-show-hidden-files} controls whether to show
hidden files by default.

@vindex x-use-old-gtk-file-dialog
  For Gtk+ version 2.4 and 2.6, you can make Emacs use the old file dialog
by setting the variable @code{x-use-old-gtk-file-dialog} to a non-@code{nil}
value.  If Emacs is built with a Gtk+ version that has only one file dialog,
the setting of this variable has no effect.

@node Tooltips
@section Tooltips
@cindex tooltips

  @dfn{Tooltips} are small windows that display text information at the
current mouse position.  They activate when there is a pause in mouse
movement.  There are two types of tooltip: help tooltips and GUD
tooltips.

  @dfn{Help tooltips} typically display over text---including the mode
line---but are also available for other parts of the Emacs frame, such
as the tool bar and menu items.

@findex tooltip-mode
  You can toggle display of help tooltips (Tooltip mode) with the
command @kbd{M-x tooltip-mode}.  When Tooltip mode is disabled, the
help text is displayed in the echo area instead.

  @dfn{GUD tooltips} show values of variables.  They are useful when
you are debugging a program.  @xref{Debugger Operation}.

@vindex tooltip-delay
  The variables @code{tooltip-delay} specifies how long Emacs should
wait before displaying a tooltip.  For additional customization
options for displaying tooltips, use @kbd{M-x customize-group
@key{RET} tooltip @key{RET}}.  @xref{X Resources}, for information on
customizing the windows that display tooltips.

@node Mouse Avoidance
@section Mouse Avoidance
@cindex avoiding mouse in the way of your typing
@cindex mouse avoidance

@vindex mouse-avoidance-mode
Mouse Avoidance mode keeps the mouse pointer away from point, to avoid
obscuring text you want to edit.  Whenever it moves the mouse, it also
raises the frame.  To use Mouse Avoidance mode, customize the variable
@code{mouse-avoidance-mode}.  You can set this to various values to
move the mouse in several ways:

@table @code
@item banish
Move the mouse to the upper-right corner on any key-press;
@item exile
Move the mouse to the corner only if the cursor gets too close,
and allow it to return once the cursor is out of the way;
@item jump
If the cursor gets too close to the mouse, displace the mouse
a random distance & direction;
@item animate
As @code{jump}, but shows steps along the way for illusion of motion;
@item cat-and-mouse
The same as @code{animate};
@item proteus
As @code{animate}, but changes the shape of the mouse pointer too.
@end table

@findex mouse-avoidance-mode
You can also use the command @kbd{M-x mouse-avoidance-mode} to enable
the mode.

@node Non-Window Terminals
@section Non-Window Terminals
@cindex non-window terminals
@cindex single-frame terminals

  On a text-only terminal, Emacs can display only one Emacs frame at a
time.  However, you can still create multiple Emacs frames, and switch
between them.  Switching frames on these terminals is much like
switching between different window configurations.

  Use @kbd{C-x 5 2} to create a new frame and switch to it; use @kbd{C-x
5 o} to cycle through the existing frames; use @kbd{C-x 5 0} to delete
the current frame.

  Each frame has a number to distinguish it.  If your terminal can
display only one frame at a time, the selected frame's number @var{n}
appears near the beginning of the mode line, in the form
@samp{F@var{n}}.

@findex set-frame-name
@findex select-frame-by-name
  @samp{F@var{n}} is in fact the frame's initial name.  You can give
frames more meaningful names if you wish, and you can select a frame
by its name.  Use the command @kbd{M-x set-frame-name @key{RET}
@var{name} @key{RET}} to specify a new name for the selected frame,
and use @kbd{M-x select-frame-by-name @key{RET} @var{name} @key{RET}}
to select a frame according to its name.  The name you specify appears
in the mode line when the frame is selected.

@node XTerm Mouse
@section Using a Mouse in Terminal Emulators
@cindex xterm, mouse support
@cindex terminal emulators, mouse support

  Some terminal emulators under X support mouse clicks in the terminal
window.  In a terminal emulator which is compatible with @code{xterm},
you can use @kbd{M-x xterm-mouse-mode} to give Emacs control over
simple use of the mouse---basically, only non-modified single clicks
are supported.  The normal @code{xterm} mouse functionality for such
clicks is still available by holding down the @kbd{SHIFT} key when you
press the mouse button.

  Xterm Mouse mode is a global minor mode (@pxref{Minor Modes}).
Repeating the command turns the mode off again.

@ignore
   arch-tag: 7dcf3a31-a43b-45d4-a900-445b10d77e49
@end ignore