Stealth fontification only occurs while the system remains unloaded.
If the system load rises above `jit-lock-stealth-load' percent, stealth
fontification is suspended. Stealth fontification intensity is controlled via
-the variable `jit-lock-stealth-nice'."
+the variable `jit-lock-stealth-nice'.
+
+If you need to debug code run from jit-lock, see `jit-lock-debug-mode'."
(setq jit-lock-mode arg)
(cond
((buffer-base-buffer)