Subject: bug#41124: 26.3; highlight regexp not working properly - not updating as you type

From: Eli Zaretskii <[email-masked]>
Date: Thu, 07 May 2020 20:58:00 +0300

> From: jan <[email-masked]>
> Date: Thu, 7 May 2020 18:32:18 +0100
> Cc: [email-masked]
> 
> Doing as you say (M-: major-mode RET) it says it is in text-mode.

Which I think is the same as Fundamental mode wrt font-lock.

You need to be in a major mode that defines font-lock settings.