Hi Vangelis,

Vangelis Evangelou <evangelou@gmail.com> writes:

> Yes, that's part of the problem. Can you please add a few new lines
> before \documentclass, so that it looks like the first picture? Then
> when you narrow again, you should get an error
> error in process sentinel: flymake--highlight-line: Wrong type argument: integer-or-marker-p, nil

This is what I see with "emacs -Q":

Since it happens with vanilla Emacs & tex-mode.el as well: Can you
please submit a bug report to Emacs with a recipe starting with "emacs
-Q", so the developers there can reproduce it?  I could re-assign this
report, but I think it makes sense to start a new one with a clear
reproducer.

TIA.  Best, Arash