Subject: bug#41441: 26.3; mhtml misbehaving font-lock extend region can cause Emacs to hang

From: Dmitry Gutov <[email-masked]>
Date: Thu, 28 May 2020 00:32:15 +0300

On 25.05.2020 19:11, Tom Tromey wrote:
> Looking at mhtml--submode-fontify-region, though, I wonder if maybe
> region extension isn't needed at all, since that function seems to
> handle sub-mode region boundaries.  So I guess that is one
> experiment that could be done.

That makes sense to me, and mirrors what mmm-mode currently does.

What if we just remove mhtml--extend-font-lock-region? Can anyone 
describe a scenario that would become broken?