bug#66655: 29.1; Clicking buttons sometimes doesn't work

[Stefan Kangas]

tomasralph2000@gmail.com writes:

> If using =display-line-numbers-mode= with the =visual= style set for it,
> sometimes clicking buttons does not actually click it. It instead shifts
> the buffer slightly, either to the left or to the right, and a mark is
> set (by clicking I refer with the mouse, specifically). You will need to
> press again in order to actually click the button.
>
> This is inconsistent, there's no guarantee that it will happen, it
> sometimes does, but it is often enough for you to be able to notice within
> just a couple of seconds of clicking through things.
>
> You can launch =emacs -Q= and run these two lines:
>
> (setq display-line-numbers-type 'visual)
> (global-display-line-numbers-mode)
>
> Then just click through buttons. A good test is to open the emacs manual
> =C-h R emacs= since it has a big index.
>
> The bug does not happen with =relative= style line numbers.

I can reproduce this on master, but it did take like 1-2 minutes of
clicking around to trigger it.

I might be making this up, but I feel like I've seen this before --
without `display-line-numbers-mode'.  Perhaps there's some rare bug that
is just more frequently triggered when that mode is on?  But I'm not
really sure about that, it's quite possible that I'm wrong.


In GNU Emacs 30.0.50 (build 1, x86_64-apple-darwin21.6.0, NS
 appkit-2113.60 Version 12.7 (Build 21G816)) of 2023-10-18 built on
 Newton.local
Repository revision: 50514298cf98fcd0dfb0d59a7e03b1ebb0d03490
Repository branch: scratch/no-purespace
Windowing system distributor 'Apple', version 10.3.2113
System Description:  macOS 12.7

Configured using:
 'configure 'LDFLAGS=-L/usr/local/opt/llvm/lib
 -L/usr/local/opt/libffi/lib' 'CPPFLAGS=-I/usr/local/opt/llvm/include
 -I/usr/local/opt/libffi/include''

Configured features:
ACL GIF GMP GNUTLS JPEG JSON LCMS2 LIBXML2 MODULES NOTIFY KQUEUE NS
PDUMPER PNG SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER WEBP
XIM ZLIB