This page is about making particular whitespace characters stand out better. Emacs comes with a standard solution: M-x whitespace-mode. See WhiteSpace. Some DetailsGNU Emacs 24 has internal variable ‘nobreak-char-display’ (turned on by default), which highlights hard space and hard hyphen characters. But the face is hardwired, and you cannot highlight only one of these chars. GNU Emacs 22 or later