Re: jit lock sit-for provokes redisplay provokes imenu

[Richard Stallman]

    After ~30s of idle time, I see imenu-update-menubar being called
    continuously by emacs.  At a guess, imenu is being triggered because
    jit-lock has kicked in.

That seems plausible.  Jit-lock does fontification by adding text
properties, and that modifies the buffer, so that the subsequent
redisplay will call imenu-update-menubar.

The obvious way to solve this is to add a feature that enables
imenu-update-menubar to determine that there have been no changes
except in text properties.  Then it could return without really doing
anything.

It could be a function buffer-chars-modified-tick,
which records the value of buffer-modified-tick as of the last
change in the characters in the buffer.

Would someone like to implement this?