If you use emacs (not xemacs) with Isabelle and would like to get the familiar colours in theory files you were used to on xemacs: here's the required custiomisation command.
Clemens --- (custom-set-faces ;; custom-set-faces was added by Custom. ;; If you edit it by hand, you could mess it up, so be careful. ;; Your init file should contain only one such instance. ;; If there is more than one, they won't work right. '(font-lock-builtin-face ((((class color) (min-colors 88) (background light)) (:foreground "Purple")))) '(font-lock-comment-face ((((class color) (min-colors 88) (background light)) (:foreground "blue4")))) '(font-lock-constant-face ((((class color) (min-colors 88) (background light)) (:foreground "red")))) '(font-lock-function-name-face ((((class color) (min-colors 88) (background light)) (:foreground "brown4")))) '(font-lock-keyword-face ((((class color) (min-colors 88) (background light)) (:foreground "red4")))) '(font-lock-preprocessor-face ((t (:foreground "blue3")))) '(font-lock-string-face ((((class color) (min-colors 88) (background light)) (:foreground "DarkGreen")))) '(font-lock-type-face ((((class color) (min-colors 88) (background light)) (:foreground "SteelBlue")))) '(font-lock-variable-name-face ((((class color) (min-colors 88) (background light)) (:foreground "magenta4")))) '(font-lock-warning-face ((((class color) (min-colors 88) (background light)) (:foreground "Red" :weight bold)))))