Emacs 24.5 on Linux. Run emacs with "emacs -Q", and then eval the following code: ------------------------------------------------------------ (setq font-lock-maximum-decoration 2 jit-lock-defer-time 0.05) (setq-default show-trailing-whitespace t) ------------------------------------------------------------ Then open the attached c file, and scroll down the buffer with key C-v C-v ... until the end of buffer. Switch to the message buffer *Message*. There are some error message as the following: ------------------------------------------------------------------------------ Error during redisplay: (jit-lock-function 3102) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 4131) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 6206) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 7252) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 7757) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 8269) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 8790) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 9312) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 10383) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 10895) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 11403) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 12446) signaled (error "Invalid search bound (wrong side of point)") Error during redisplay: (jit-lock-function 14009) signaled (error "Invalid search bound (wrong side of point)") --------------------------------------------------------------------------------