Each Emacs window displays one Emacs buffer at any time. A single buffer may appear in more than one window; if it does, any changes in its text are displayed in all the windows where it appears. But these windows can show different parts of the buffer, because each window has its own value of point. At any time, one Emacs window is the selected window; the buffer this window is displaying is the current buffer. On graphical displays, the point is indicated by a solid blinking cursor in the selected window, and by a hollow box in non-selected windows. On text terminals, the cursor is drawn only in the selected window. Cursor Display. Commands to move point affect the value of point for the selected Emacs window only. They do not change the value of point in other Emacs windows, even those showing the same buffer. The same is true for buffer-switching commands such as C-x b; they do not affect other windows at all. However, there are other commands such as 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) C-h f (describe-function) and C-x C-b (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, they all have the same value for the mark, because each buffer has only one mark position. Each window has its own mode line, which displays the buffer name, modification status and major and minor modes of the buffer that is displayed in the window. The selected window's mode line appears in a different color. Mode Line, for details.

C-x 2

Split the selected window into two windows, one above the other (split-window-below).

C-x 3

Split the selected window into two windows, positioned side by side (split-window-right).

C-mouse-2

In the mode line of a window, split that window.

C-x 2 (split-window-below) splits the selected window into two windows, one above the other. After splitting, the selected window is the upper one, and the newly split-off window is below. Both windows have the same value of point as before, and display the same portion of the buffer (or as close to it as possible). If necessary, the windows are scrolled to keep point on-screen. By default, the two windows each get half the height of the original window. A positive numeric argument specifies how many lines to give to the top window; a negative numeric argument specifies how many lines to give to the bottom window. If you change the variable split-window-keep-point to nil, C-x 2 instead adjusts the portion of the buffer displayed by the two windows, as well as the value of point in each window, in order to keep the text on the screen as close as possible to what it was before; furthermore, if point was in the lower half of the original window, the bottom window is selected instead of the upper one. C-x 3 (split-window-right) splits the selected window into two side-by-side windows. The left window is the selected one; the right window displays the same portion of the same buffer, and has the same value of point. A positive numeric argument specifies how many columns to give the left window; a negative numeric argument specifies how many columns to give the right window. When you split a window with C-x 3, each resulting window occupies less than the full width of the frame. If it becomes too narrow, the buffer may be difficult to read if continuation lines are in use (Continuation Lines). Therefore, Emacs automatically switches to line truncation if the window width becomes narrower than 50 columns. This truncation occurs regardless of the value of the variable truncate-lines (Line Truncation); it is instead controlled by the variable truncate-partial-width-windows. If the value of this variable is a positive integer (the default is 50), that specifies the minimum total width for a partial-width window before automatic line truncation occurs; if the value is nil, automatic line truncation is disabled; and for any other non-nil value, Emacs truncates lines in every partial-width window regardless of its width. The total width of a window is in column units as reported by window-total-width (Window Sizes), it includes the fringes, the continuation and truncation glyphs, the margins, and the scroll bar. On text terminals, side-by-side windows are separated by a vertical divider which is drawn using the vertical-border face. If you click C-mouse-2 in the mode line of a window, that splits the window, putting a vertical divider where you click. Depending on how Emacs is compiled, you can also split a window by clicking C-mouse-2 in the scroll bar, which puts a horizontal divider where you click (this feature does not work when Emacs uses GTK+ scroll bars). By default, when you split a window, Emacs gives each of the resulting windows dimensions that are an integral multiple of the default font size of the frame. That might subdivide the screen estate unevenly between the resulting windows. If you set the variable window-resize-pixelwise to a non-nil value, Emacs will give each window the same number of pixels (give or take one pixel if the initial dimension was an odd number of pixels). Note that when a frame's pixel size is not a multiple of the frame's character size, at least one window may get resized pixelwise even if this option is nil.

C-x o

Select another window (other-window).

C-x O

Select another window, backwards (other-window-backward).

C-M-v

Scroll the next window upward (scroll-other-window).

C-M-S-v

Scroll the next window downward (scroll-other-window-down).

C-M-S-l

Recenter the next window (recenter-other-window).

mouse-1

mouse-1, in the text area of a window, selects the window and moves point to the position clicked. Clicking in the mode line selects the window without moving point in it.

With the keyboard, you can switch windows by typing C-x o (other-window). That is an o, for "other", not a zero. When there are more than two windows, this command moves through all the windows in a cyclic order, generally top to bottom and left to right. After the rightmost and bottommost window, it goes back to the one at the upper left corner. A numeric argument means to move several steps in the cyclic order of windows. A negative argument moves around the cycle in the opposite order. When the minibuffer is active, the minibuffer window is the last window in the cycle; you can switch from the minibuffer window to one of the other windows, and later switch back and finish supplying the minibuffer argument that is requested. Minibuffer Edit. C-x O is similar, but defaults to the opposite order. The other-window command will normally only switch to the next window in the current frame (unless otherwise configured). If you work in a multi-frame environment and you want windows in all frames to be part of the cycle, you can rebind C-x o to the next-window-any-frame command. (Rebinding, for how to rebind a command.) The usual scrolling commands (Display) apply to the selected window only, but there are also commands to scroll the next window. C-M-v (scroll-other-window) scrolls the window that C-x o would select. In other respects, the command behaves like C-v; both move the buffer text upward relative to the window, and take positive and negative arguments. (In the minibuffer, C-M-v scrolls the help window associated with the minibuffer, if any, rather than the next window in the standard cyclic order; Minibuffer Edit.) C-M-S-v (scroll-other-window-down) scrolls the next window downward in a similar way. Likewise, C-M-S-l (recenter-other-window) behaves like C-l (recenter-top-bottom) in the next window. If you set mouse-autoselect-window to a non-nil value, moving the mouse over a different window selects that window. This feature is off by default.

C-x 4 is a prefix key for a variety of commands that switch to a buffer in a different window—either another existing window, or a new window created by splitting the selected window. Window Choice, for how Emacs picks or creates the window to use.

C-x 4 b bufname RET

Select buffer bufname in another window (switch-to-buffer-other-window). Select Buffer.

C-x 4 C-o bufname RET

Display buffer bufname in some window, without trying to select it (display-buffer). Displaying Buffers, for details about how the window is chosen.

C-x 4 f filename RET

Visit file filename and select its buffer in another window (find-file-other-window). Visiting.

C-x 4 d directory RET

Select a Dired buffer for directory directory in another window (dired-other-window). Dired.

C-x 4 m

Start composing a mail message, similar to C-x m (Sending Mail), but in another window (compose-mail-other-window).

C-x 4 .

Find the definition of an identifier, similar to M-. (Xref), but in another window (xref-find-definitions-other-window).

C-x 4 r filename RET

Visit file filename read-only, and select its buffer in another window (find-file-read-only-other-window). Visiting.

C-x 4 4

A more general prefix command affects the buffer displayed by a subsequent command invoked after this prefix command (other-window-prefix). It requests the buffer displayed by a subsequent command to be shown in another window.

C-x 4 1

This general prefix command requests the buffer of the next command to be displayed in the same window.

C-x 0

Delete the selected window (delete-window).

C-x 1

Delete all windows in the selected frame except the selected window (delete-other-windows).

C-x 4 0

Delete the selected window and kill the buffer that was showing in it (kill-buffer-and-window). The last character in this key sequence is a zero.

C-x w 0 RET buffer RET

Delete windows showing the specified buffer.

C-x ^

Make selected window taller (enlarge-window).

C-x @}

Make selected window wider (enlarge-window-horizontally).

C-x @{

Make selected window narrower (shrink-window-horizontally).

C-x -

Shrink this window if its buffer doesn't need so many lines (shrink-window-if-larger-than-buffer).

C-x +

Balance the sizes of all the windows of the selected frame (balance-windows).

To delete the selected window, type C-x 0 (delete-window). (That is a zero.) Once a window is deleted, the space that it occupied is given to an adjacent window (but not the minibuffer window, even if that is active at the time). Deleting the window has no effect on the buffer it used to display; the buffer continues to exist, and you can still switch to it with C-x b. The option delete-window-choose-selected controls which window is chosen as the new selected window instead (Deleting Windows). C-x 4 0 (kill-buffer-and-window) is a stronger command than C-x 0; it kills the current buffer and then deletes the selected window. C-x 1 (delete-other-windows) deletes all the windows, except the selected one; the selected window expands to use the whole frame. (This command cannot be used while the minibuffer window is active; attempting to do so signals an error.) M-x delete-windows-on deletes windows that show a specific buffer. It prompts for the buffer, defaulting to the current buffer. With prefix argument of zero, C-u 0, this command deletes windows only on the current display's frames. The command C-x ^ (enlarge-window) makes the selected window one line taller, taking space from a vertically adjacent window without changing the height of the frame. With a positive numeric argument, this command increases the window height by that many lines; with a negative argument, it reduces the height by that many lines. If there are no vertically adjacent windows (i.e., the window is at the full frame height), that signals an error. The command also signals an error if you attempt to reduce the height of any window below a certain minimum number of lines, specified by the variable window-min-height (the default is 4). Similarly, C-x @} (enlarge-window-horizontally) makes the selected window wider, and @kbd{C-x @{} (shrink-window-horizontally) makes it narrower. These commands signal an error if you attempt to reduce the width of any window below a certain minimum number of columns, specified by the variable window-min-width (the default is 10). Mouse clicks on the mode line (Mode Line Mouse) or on window dividers (Window Dividers) provide another way to change window heights and to split or delete windows. C-x - (shrink-window-if-larger-than-buffer) reduces the height of the selected window, if it is taller than necessary to show the whole text of the buffer it is displaying. It gives the extra lines to other windows in the frame. You can also use C-x + (balance-windows) to balance the sizes of all the windows of the selected frame (with the exception of the minibuffer window, Minibuffer). This command makes each horizontal pair of adjacent windows the same height, and each vertical pair of adjacent windows the same width.

It is a common Emacs operation to display or pop up some buffer in response to a user command. There are several different ways in which commands do this. Many commands, like C-x C-f (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 displaying the desired buffer there. Such commands, which include the various help commands (Help), work by calling display-buffer internally. Window Choice, for details. Other commands do the same as display-buffer, and additionally select the displaying window so that you can begin editing its buffer. The command M-g M-n (next-error) is one example (Compilation Mode). Such commands work by calling the function pop-to-buffer internally. Switching to a Buffer in a Window. Commands with names ending in -other-window behave like display-buffer, except that they never display in the selected window, perhaps splitting the selected window to create a new one (Window Choice). Several of these commands are bound in the C-x 4 prefix key (Pop Up Window). Commands with names ending in -other-frame behave like display-buffer, except that they (i) never display in the 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 C-x 5 prefix key. Sometimes, a window is "dedicated" to its current buffer. Dedicated Windows. display-buffer will avoid reusing dedicated windows most of the time. This is indicated by a d in the mode line (Mode Line). A window can also be strongly dedicated, which prevents any changes to the buffer displayed in the window. This is indicated by a D in the mode line. Usually, dedicated windows are used to display specialized buffers, but dedication can sometimes be useful interactively. For example, when viewing errors with M-g M-n next-error, newly displayed source code may replace a buffer you want to refer to. If you dedicate a window to that buffer, the command (through display-buffer) will prefer to use a different window instead. You can use the command C-x w d (toggle-window-dedicated) to toggle whether the selected window is dedicated to the current buffer. With a prefix argument, it makes the window strongly dedicated.

(setopt
 display-buffer-alist
 '(("\\*Completions\\*" display-buffer-below-selected)))

Winner mode is a global minor mode that records the changes in the window configuration (i.e., how the frames are partitioned into windows), so that you can undo them. You can toggle Winner mode with M-x winner-mode, or by customizing the variable winner-mode. When the mode is enabled, C-c left (winner-undo) undoes the last window configuration change. If you change your mind while undoing, you can redo the changes you had undone using C-c right (M-x winner-redo). To prevent Winner mode from binding C-c left and C-c right, you can customize the variable winner-dont-bind-my-keys to a non-nil value. By default, Winner mode stores a maximum of 200 window configurations per frame, but you can change that by modifying the variable winner-ring-size. If there are some buffers whose windows you wouldn't want Winner mode to restore, add their names to the list variable winner-boring-buffers or to the regexp winner-boring-buffers-regexp. Follow mode (M-x follow-mode) synchronizes several windows on the same buffer so that they always display adjacent sections of that buffer. Follow Mode. The Windmove package defines commands for moving directionally between neighboring windows in a frame. M-x windmove-right selects the window immediately to the right of the currently selected one, and similarly for the left, up, and down counterparts. windmove-default-keybindings binds these commands to S-right etc.; doing so disables shift selection for those keys (Shift Selection). In the same way as key bindings can be defined for commands that select windows directionally, you can use windmove-display-default-keybindings to define keybindings for commands that specify in what direction to display the window for the buffer that the next command is going to display. Also there is windmove-delete-default-keybindings to define keybindings for commands that delete windows directionally, and windmove-swap-states-default-keybindings that defines key bindings for commands that swap the window contents of the selected window with the window in the specified direction. The command M-x compare-windows lets you compare the text shown in different windows. Comparing Files. Scroll All mode (M-x scroll-all-mode) is a global minor mode that causes scrolling commands and point motion commands to apply to every single window.

The command global-tab-line-mode toggles the display of a tab line on the top screen line of each window. The Tab Line shows special buttons ("tabs") for each buffer that was displayed in a window, and allows switching to any of these buffers by clicking the corresponding button. Clicking on the + icon adds a new buffer to the window-local tab line of buffers, and clicking on the x icon of a tab deletes it. The mouse wheel on the tab line scrolls the tabs horizontally. Touch screen input (Other Input) can also be used to interact with the "tab line". Long-pressing (Touchscreens) a tab will display a context menu with items that operate on the tab that was pressed; tapping a tab itself will result in switching to that tab's buffer, and tapping a button on the tab line will behave as if it was clicked with mouse-1. Selecting the previous window-local tab is the same as typing C-x =LEFT= (previous-buffer), selecting the next tab is the same as C-x RIGHT (next-buffer). Both commands support a numeric prefix argument as a repeat count. You can customize the variable tab-line-tabs-function to define the preferred contents of the tab line. By default, it displays all buffers previously visited in the window, as described above. But you can also set it to display a list of buffers with the same major mode as the current buffer, or to display buffers grouped by their major mode, where clicking on the mode name in the first tab displays a list of all major modes where you can select another group of buffers. Note that the Tab Line is different from the Tab Bar (Tab Bars). Whereas tabs on the Tab Bar at the top of each frame are used to switch between window configurations containing several windows with buffers, tabs on the Tab Line at the top of each window are used to switch between buffers in the window. Also note that the tab line displays in the same space as the window tool bar, so only one of them can be displayed at any given time, unless you customize the value of tab-line-format in Lisp to add (:eval (tab-line-format)) to tab-line-format. Mode Line Format.

The command global-window-tool-bar-mode toggles the display of a tool bar at the top of each window. When enabled, multiple windows can display their own tool bar simultaneously. To conserve space, a window tool bar is hidden if there are no buttons to show, i.e. if tool-bar-map is nil. If you want to toggle the display of a window tool bar for only some buffers, run the command window-tool-bar-mode in those buffers. This is useful to put in a mode hook. For example, if you want the window tool bar to appear only for buffers that do not represent files and have a custom tool bar, you could add the following code to your init file (Init File):

(add-hook 'special-mode-hook 'window-tool-bar-mode)

On graphical displays the window tool bar can be displayed in several different styles. By default, the window tool bar displays items as just images. To impose a specific style, customize the variable window-tool-bar-style. On text-only displays the window tool bar only shows text for each button even if another style is specified. Emacs can also display a single tool bar at the top of frames (Tool Bars). Note that the window tool bar displays in the same space as the tab line, so only one of them can be displayed at any given time, unless you customize the value of tab-line-format to add (:eval (window-tool-bar-string)) to tab-line-format. Mode Line Format.