Subject: bug#56682: Fix the long lines font locking related slowdowns

From: Eli Zaretskii <[email-masked]>
Date: Tue, 02 Aug 2022 19:14:04 +0300

> Date: Tue, 02 Aug 2022 14:57:25 +0000
> From: Gregory Heytings <[email-masked]>
> cc: Eli Zaretskii <[email-masked]>, [email-masked], 
>     [email-masked]
> 
> > Regarding the long-standing bug reports, we did solve a bunch of issues 
> > already. One major one, IIUC, was redisplay of already fontified text on 
> > long lines.
> 
> Try to open the dictionary.json with Emacs on master a month ago.

I believe it can also be done with the current master, just after
setting long-line-threshold to the nil value.  Right?