Hi I had the following in my emacs.org and it caused under certain conditions a complete crash from emacs: ,---- | ** Fancier Code Block Delimiters | Essentially from Eric Schulte ([O] Prettier (or at least fancier) code block delimiters) | #+begin_src emacs-lisp | (defun rmk/prettier-org-code-blocks () | (interactive) | (font-lock-add-keywords nil | '(("\\(\+begin_src\\)" | (0 (progn (compose-region (match-beginning 1) (match-end 1) ?<) | nil))) | ("\\(\+end_src\\)" | (0 (progn (compose-region (match-beginning 1) (match-end 1) ?>) | nil)))))) | (add-hook 'org-mode-hook 'rmk/prettier-org-code-blocks) | #+end_src `---- The steps were: 1) create new header 2) create new