auto-dim-other-buffers.el

The auto-dim-other-buffers-mode is a global minor mode which makes windows without focus less prominent. With many windows in a frame, the idea is that this mode helps recognise which is the selected window by providing a non-intrusive but still noticeable visual indicator.

The preferred way to install the mode is by grabbing auto-dim-other-buffers package form NonGNU ELPA:

M-x package-install RET auto-dim-other-buffers RET

Once installed, enable the mode with:

M-x auto-dim-other-buffers-mode RET

To make it enabled every time Emacs starts, add the following to Emacs initialisation file (typically ~/.emacs or ~/.emacs.d/init.el):

(add-hook 'after-init-hook (lambda ()
  (when (fboundp 'auto-dim-other-buffers-mode)
    (auto-dim-other-buffers-mode t))))

To configure how dimmed buffers look, customise auto-dim-other-buffers-face. This can be accomplished by:

M-x customize-face RET auto-dim-other-buffers-face RET

More options can be found in auto-dim-other-buffers customisation group which can be accessed with:

M-x customize-group RET auto-dim-other-buffers RET

Note that despite it’s name, since Emacs 27 the mode operates on windows rather than buffers. I.e. selected window is highlighted and all other windows are dimmed even if they display the same buffer.