bug#2022: 23.0.60; Rmail buffer marked modified after saving it

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Cc: 2022@emacsbugs.donarmstrong.com
> Date: Sun, 25 Jan 2009 00:57:04 -0500
> 
> Eli Zaretskii wrote:
> 
> > Emacs does not elsewhere consider seeing a file as its modification.
> > Why should Rmail be different?
> 
> Because seeing a file (for the first time) modifies the
> X-RMAIL-ATTRIBUTES: header, which is stored in the file.

The old (pre-mbox) Rmail also had the unseen attribute, but it never
marked the Rmail buffer modified when it was removed.  So this is a
change in behavior, and I can't say I like it.

I don't think we want to regard seeing a message as a modification,
since the body of the message does not change a bit.  But if we do
make this change, at the very least, it should have been implemented
as an option, and/or via an idle timer, so that just paging thru many
messages does not automatically mark them as ``seen'', although no
human could possibly ``see'' a message in a fraction of a second.