Hi bug-gnu-emacs, If I create a file temp.txt containing the following: -*- prettify-symbols-alist: (("R_PO" 8477 (Br . cl) 8804)); -*- !!! R_PO !!! and run ‘emacs-24.5 -Q temp.txt -f prettify-symbols-mode’, I observe a surprising display bug: when I move the point across the second line, as soon as the point reaches the blank space after “R_PO”, I see a second ℝ displayed instead of the third “!”. Concretely, the line looks like “!!! ℝ≤ !!!” until I reach the second blank, and then it changes to “!!ℝ ℝ≤ !!!”. Resizing the window fixes the issue until the next cursor blink. Additionally, when the point is on R_PO, the point disappears — and taking a screenshot makes the prettified R_PO (ℝ≤) disappear, too (?!). Is this a known issue? Can anyone else reproduce it? I have attached a few pictures (all of them show the same buffer text) — let me know if I can provide any other info! Cheers, Clément. In GNU Emacs 26.0.50 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.18.9) of 2017-04-16 built on clem-w50-mint Repository revision: d1a65963ff50d2ebae87ac559514e19788ffc1cc Windowing system distributor 'The X.Org Foundation', version 11.0.11804000 System Description: Linux Mint 18.1 Serena Recent messages: For information about GNU Emacs and the GNU system, type C-h C-a. Configured features: XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 LIBSYSTEMD Important settings: value of $LC_MONETARY: en_DK.UTF-8 value of $LC_NUMERIC: en_DK.UTF-8 value of $LC_TIME: en_DK.UTF-8 value of $LANG: en_US.UTF-8 value of $XMODIFIERS: @im=ibus locale-coding-system: utf-8-unix Major mode: Lisp Interaction Minor modes in effect: tooltip-mode: t global-eldoc-mode: t electric-indent-mode: t mouse-wheel-mode: t tool-bar-mode: t menu-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t line-number-mode: t transient-mark-mode: t Load-path shadows: None found. Features: (shadow sort mail-extr emacsbug message puny seq byte-opt subr-x gv bytecomp byte-compile cl-extra help-mode cconv cl-loaddefs pcase cl-lib dired dired-loaddefs format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils time-date mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese composite charscript case-table epa-hook jka-cmpr-hook help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs button faces cus-face macroexp files text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote dbusbind inotify dynamic-setting system-font-setting font-render-setting move-toolbar gtk x-toolkit x multi-tty make-network-process emacs) Memory information: ((conses 16 96057 5153) (symbols 48 20438 1) (miscs 40 40 129) (strings 32 18025 4822) (string-bytes 1 576763) (vectors 16 14137) (vector-slots 8 485275 4358) (floats 8 48 68) (intervals 56 203 0) (buffers 976 11) (heap 1024 47991 1074))