bug#69534: Scrolling up causes all text to shift drastically when cursor hits bottom of viewable area.

[Arkdae via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

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What I am trying to say is, when the point gets to the bottom of a
window, and you move the scroll bar up the smallest amount you can,
then the point and the text all move to the middle. Then you move the
scroll bar up one more tiny amount and the text shifts back down to
where it should have been for normal line scrolling.

But, really if you don't see it, you don't have the problem. It's
reasonably obvious. It is a good point that you made, and so I tried a
different GTK theme. I believe the default is Adwaita, so I started
Emacs like so:

GTK_THEME=Adiaita emacs -Q

But it still occurs, but maybe not quite as often.

Otherwise, I can't say that I am aware of any customization to Emacs.
I'm rather new to using it. The only extensions I use are slime and
ace-window.

On Mon, 2024-03-04 at 14:15 +0200, Eli Zaretskii wrote:
> > Date: Sun, 03 Mar 2024 15:56:36 +0000
> > From:  Arkdae via "Bug reports for GNU Emacs,
> >  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> > 
> > Start 'emacs -Q'. Open a long document which is longer than can fit
> > in
> > the window all at once. C-x 2 to split into two windows. Drag with
> > the
> > mouse on the information bar with button one to shrink the bottom
> > window a bit. Then grab the scroll bar in the top window and drag
> > up.
> > 
> > The cursor reaches the bottom. Then I slowly scroll one more pixel
> > up
> > and all of the text contents are repositioned with the cursor at
> > the
> > middle. The next pixel scrolled up keeps the cursor in the middle
> > and
> > corrects the text to where it should have been.
> 
> I cannot reproduce this, but then I don't think I understand what you
> mean by "scroll one more pixel up".  AFAIK, scrolling text in Emacs
> works by lines, not by pixels.  Maybe a GTK3 build allows pixelwise
> scrolling via the scroll-bar?  If so, this could be specific to GTK3
> builds or something.
> 
> Are you sure you don't have some local changes wrt stock Emacs 29.2,
> or maybe activated some non-default feature that affects scrolling?


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