*** Font Lock support modes
Font Lock can be configured to use Fast Lock mode and Lazy Lock mode (see
below) in a flexible way. Rather than adding the appropriate function to the
hook font-lock-mode-hook, you can use the new variable font-lock-support-mode
to control which modes have Fast Lock mode or Lazy Lock mode turned on when
Font Lock mode is enabled.
For example, to use Fast Lock mode when Font Lock mode is turned on, put:
(setq font-lock-support-mode 'fast-lock-mode)
in your ~/.emacs.