bug#62676: Setting `scroll-bar-width` Doesn't Take Effect Immediately

bug#62676: Setting `scroll-bar-width` Doesn't Take Effect Immediately

[Shynur Xie]

Example:

```
$ emacs -Q
```

Now the current buffer is "*scratch*", evaluating:

```
(setq scroll-bar-width 50)
```

changes nothing.

Instead, user need to switch to another buffer and then switch back:

```
(progn
  (setq scroll-bar-width 50)
  (switch-to-buffer "*Messages*")
  (switch-to-buffer "*scratch*"))
```

________________________________________

emacs-version: 28.2
system-configuration: x86_64-w64-mingw32

bug#62676: Setting `scroll-bar-width` Doesn't Take Effect Immediately

[Eli Zaretskii]

tags 62676 notabug
thank

> From: Shynur Xie <one.last.kiss@outlook.com>
> Date: Wed, 5 Apr 2023 08:18:00 +0000
> 
> Example:
> 
> ```
> $ emacs -Q
> ```
> 
> Now the current buffer is "*scratch*", evaluating:
> 
> ```
> (setq scroll-bar-width 50)
> ```
> 
> changes nothing.
> 
> Instead, user need to switch to another buffer and then switch back:
> 
> ```
> (progn
>   (setq scroll-bar-width 50)
>   (switch-to-buffer "*Messages*")
>   (switch-to-buffer "*scratch*"))
> ```

This is the expected and documented behavior.  From the ELisp
Reference manual:

     If you do not specify a window’s scroll bar settings via
  ‘set-window-scroll-bars’, the buffer-local variables
  ‘vertical-scroll-bar’, ‘horizontal-scroll-bar’, ‘scroll-bar-width’ and
  ‘scroll-bar-height’ in the buffer being displayed control the window’s
  scroll bars.  The function ‘set-window-buffer’ examines these variables.
  If you change them in a buffer that is already visible in a window, you
  can make the window take note of the new values by calling
  ‘set-window-buffer’ specifying the same buffer that is already
  displayed.

Your last recipe calls set-window-buffer indirectly, so it succeeds
where the original recipe failed.

bug#62676: Setting `scroll-bar-width` Doesn't Take Effect Immediately

[Eli Zaretskii]

> From: Shynur Xie <one.last.kiss@outlook.com>
> Date: Wed, 5 Apr 2023 09:18:58 +0000
> 
> Thanks.  No further questions.

Thanks, closing.