Subject: bug#44983: Truncate long lines of grep output

From: Eli Zaretskii <[email-masked]>
Date: Fri, 29 Apr 2022 15:22:18 +0300

> From: Lars Ingebrigtsen <[email-masked]>
> Cc: Eli Zaretskii <[email-masked]>,  [email-masked],  [email-masked]
> Date: Fri, 29 Apr 2022 13:39:41 +0200
> 
> I thought I remembered there was a way to say to font-lock "ignore this
> bit of the buffer", but I can't find it now.  Do I misremember?

Make the text invisible?

If that doesn't help either, I suggest to profile the code, because it
could be the slow display is due to something else.