Re: highlight-changes-mode

[Richard Stallman]

    I added a new keyword :only-new EXPR which allows restricting
    a change of mode to new only new buffers if EXPR is non-nil.
    (So the default behaviour, without this keyword, is unchanged.)

If we want that functionality, this is a clean way of providing it.  I
think the real question is which way we want global minor modes to
work.  Do we want the global mode command to affect only buffers
created subsequently?  Do we want it to affect all existing buffers?
Only existing buffers in which the user has not specified any
setting for the mode?

Is there a good reason why global-highlight-changes should
not be like Global Font Lock mode, and affect all buffers
where it is applicable?