bug#74435: Scrollbar width is not respected on Windows

bug#74435: Scrollbar width is not respected on Windows

[Johann Höchtl]

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On Emacs Windows


It seems like the observation of
https://lists.libreplanet.org/archive/html/help-gnu-emacs/2023-11/msg00109.html
has never been reported as a bug.

This issue is real. When I spilt a Windows with C-x 3 and save the desktop
and re-open the desktop, the scrollbar separating the two windows is
broader than it used to be before saving.

When I manually open the .emacs.desktop file and delete the setq
scroll-bar-width and reload the desktop, the width is back to normal.

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bug#74435: Scrollbar width is not respected on Windows

[Eli Zaretskii]

> From: Johann Höchtl <johann.hoechtl@gmail.com>
> Date: Tue, 19 Nov 2024 13:01:44 +0100
> 
> On Emacs Windows
> 
> It seems like the observation of
> https://lists.libreplanet.org/archive/html/help-gnu-emacs/2023-11/msg00109.html
> has never been reported as a bug.

Because, as I responded there, I couldn't reproduce the problem.

> This issue is real. When I spilt a Windows with C-x 3 and save the desktop and re-open the desktop, the
> scrollbar separating the two windows is broader than it used to be before saving.

I still cannot reproduce this.  maybe this has something to do with
the display settings?  Like HiDPI, perhaps?

> When I manually open the .emacs.desktop file and delete the setq scroll-bar-width and reload the
> desktop, the width is back to normal.

What is the value of scroll-bar-width recorded in the desktop file,
and what does the below yield if you type it after "C-x 3" before
saving desktop?

  M-: (frame-parameter nil 'scroll-bar-width) RET

Adding Cecilio, in case he has an idea why this could happen, or can
suggest a way to debug this.

bug#74435: Scrollbar width is not respected on Windows

[Cecilio Pardo]

On 21/11/2024 11:48, Eli Zaretskii wrote:
>> From: Johann Höchtl <johann.hoechtl@gmail.com>
>> Date: Tue, 19 Nov 2024 13:01:44 +0100
>>
>> On Emacs Windows
>>
>> It seems like the observation of
>> https://lists.libreplanet.org/archive/html/help-gnu-emacs/2023-11/msg00109.html
>> has never been reported as a bug.
> 
> Because, as I responded there, I couldn't reproduce the problem.
> 
>> This issue is real. When I spilt a Windows with C-x 3 and save the desktop and re-open the desktop, the
>> scrollbar separating the two windows is broader than it used to be before saving.
> 
> I still cannot reproduce this.  maybe this has something to do with
> the display settings?  Like HiDPI, perhaps?

I can reproduce this on Windows 11. I'm looking into it.

bug#74435: Scrollbar width is not respected on Windows

[Eli Zaretskii]

> Date: Thu, 21 Nov 2024 15:57:14 +0100
> Cc: 74435@debbugs.gnu.org
> From: Cecilio Pardo <cpardo@imayhem.com>
> 
> On 21/11/2024 11:48, Eli Zaretskii wrote:
> >> From: Johann Höchtl <johann.hoechtl@gmail.com>
> >> Date: Tue, 19 Nov 2024 13:01:44 +0100
> >>
> >> On Emacs Windows
> >>
> >> It seems like the observation of
> >> https://lists.libreplanet.org/archive/html/help-gnu-emacs/2023-11/msg00109.html
> >> has never been reported as a bug.
> > 
> > Because, as I responded there, I couldn't reproduce the problem.
> > 
> >> This issue is real. When I spilt a Windows with C-x 3 and save the desktop and re-open the desktop, the
> >> scrollbar separating the two windows is broader than it used to be before saving.
> > 
> > I still cannot reproduce this.  maybe this has something to do with
> > the display settings?  Like HiDPI, perhaps?
> 
> I can reproduce this on Windows 11. I'm looking into it.

Thanks, that's good news.  It would be interesting to know why I
couldn't reproduce that here (also Windows 11).

bug#74435: Scrollbar width is not respected on Windows

[Cecilio Pardo]

I have tracked (I think) this problem to the function 
frame.c:gui_set_scroll_bar_width

If the new value for the scrollbars width is equal to the current one, 
then it resets width to the default size.

The 'if' tests for arg != FRAME_CONFIG_SCROLL_BAR_WIDTH(f).
That is, if arg is equal to current width, the 'else' path is taken, 
which resets to default.

I suppose this should test for arg != "DEFAULT_WIDTH", but I don't know 
where to find that.

Maybe you could not reproduce it because your scrollbars are on the 
default size?