Subject: bug#6429: 23.2; Scrollbars slow emacs down

From: Stefan Kangas <[email-masked]>
Date: Sun, 7 Jul 2019 14:24:43 +0200

DPX-Infinity <[email-masked]> writes:

> Steps to reproduce:
>  - Launch emacs if it is not launched
>  - Toggle scrollbars mode if it is turned off
>  - Open new buffer or empty file and try to type something
> You'll get a latency between key press and text output. If you
> hold the key, this behaviour will be more noticeable. Opening a file
> which fills even a half of the window helps. This happens either when
> scrollbar is on the right side or on the left. Turning scrollbars off helps.
>
> First, this problem appears only in large windows, 200x80 symbols or
> so. Second, it depends more on window height than on width: when
> you split the window horizontally, this effect is reduced, but vertical
> split does nothing. Third, the more the amount of text is in the
> window, the better the performance is. It seems, that it depends not
> only on one window, but on all windows that are on the screen now: e.g.,
> if you split window and load some file which fills one of the windows,
> you'll notice that this effect is reduced. Finally, if you turn off
> scrollbars mode this problem completely vanishes: text typing becomes as
> smooth as always. I also haven't met this behaviour in older
> versions. I don't remember when exactly this behaviour started, but it
> certainly was normal in 22.x branch.

Hi,

I've tried to reproduce this using the latest version of Emacs (26.2)
but have been unable to do so.

I see that this bug was reported 9 years ago.  Can you still reproduce
it on the newest version of Emacs?

I can see in the bug report some minor-modes that would not have been
enabled by default.  If you can still reproduce this, could you please
provide an exact recipe to do so starting from "emacs -Q"?

If I don't hear back from you in a couple of weeks, I'll just close this
as unreproducible.

Thanks,
Stefan Kangas