Re: header-line-format hacking

[ytrewq1]

Thien-Thi Nguyen  writes:

> more idiomatic is to have the minor mode define a variable
> that has value nil when the minor mode is inactive.  then,
> you add the variable to the formatting tree unconditionally,
> and the display engine takes care of things automatically.

I don't think I quite follow you.  Do you mean that the minor 
mode code should not be modifying header-line-format?  If it's
not supposed to, does that mean each user should add something
to their .emacs to define header-line-format?