bug#81561: 31.0.91; speedbar-window-mode creates stale idle timers

> From: Vincenzo Pupillo <[email protected]>
> Cc: Eli Zaretskii <[email protected]>, [email protected]
> Date: Fri, 14 Aug 2026 15:44:19 +0200
> 
> In data venerdì 14 agosto 2026 02:54:28 Ora legale dell’Europa centrale, J.P. 
> ha scritto:
> > Daniel Mendler via "Bug reports for GNU Emacs, the Swiss army knife of
> > 
> > text editors" <[email protected]> writes:
> > > "J.P." <[email protected]> writes:
> > >> P.S. If it's determined that this bug is not in fact directly related to
> > >> the introduction of `speedbar-window-mode', perhaps it's better to
> > >> revert a56e964941f "Speedbar: no more stale idle timers (bug#81561)" on
> > >> Emacs 31 and instead apply any future attempted fixes to master?
> > > 
> > > The bug is at least exacerbated by speedbar-window-mode. Basically
> > > speedbar-window-mode always causes a stale timer. Without window mode I
> > > see only few stale timers.
> > > 
> > > I think using a kill-buffer-hook as Vincenzo proposed in his last patch
> > > is the way to go.
> > 
> > Makes sense. And it complements what `dframe-frame-mode' does with
> > `kill-buffer-hook' to perform teardown for `speedbar-frame-mode'. It
> > also seems likely (to me) that confining `dframe-set-timer' to
> > `speedbar-buffer' proves similarly important because `speedbar-timer-fn'
> > can otherwise run in any buffer when the thing fires.
> Ciao, 
> I couldn't have explained it any better...
> I'm glad these simple changes have helped simplify ERC a little bit.

Thanks, I've now installed the patch on the emacs-31 release branch,
and closing the bug.

Vincenzo, please in the future try to observe more closely our
conventions regarding 2 spaces between sentences, I needed to fix
several cases of that in the commit log message.