I think I found the problem. As it turns out you can easily explore the phenomenon by creating a dummy function, attaching it to the font-lock-mode-hook and putting a debug-on-entry breakpoint there. (defun foo () (message "font-lock-mode-hook evaluated")) (add-hook 'font-lock-mode-hook 'foo) M-x debug-on-entry foo Then get a buffer and revert it. For buffer reversion, I see font-lock being called via the font-lock-revert-cleanup alias which looks like (from font-lock.el): ;; If the buffer has just been reverted, normally that turns off ;; Font Lock mode. So turn the mode back on if necessary. (defalias 'font-lock-revert-cleanup 'turn-on-font-lock) It appears that the comment is no longer operative as I see the buffer being font-locked when normal-mode is called initially. So this appears to be a different problem than the one I was originally thinking of. Could people who are experiencing this problem please try eliminating the font-lock-revert-cleanup function and see what, if anything, breaks? Ie. after starting XEmacs and loading font-lock.elc, evaluate the following in *scratch*: (defun font-lock-revert-cleanup ())