Hi Jean and Tassilo,

>>>>> jfbu <jfbu@free.fr> writes:
>> Now that you've mentioned it, I remember I wanted to do that change also
>> in the past and Keita-san stopped me from doing so for exactly this
>> reason.

Yes, I did. ;-)

> Would it make sense to apply these rules:

> 1. a $ in comments can never start math mode
> 2. but it can and will always stop math mode

That is a clean idea and, fortunately, easy to implment. Could you test
the attached patch?

One remark: This patch does not follow rigorously your proposition. A $
in comments does not stop math mode if it is preceded by odd numbers of
$'s like this:
foo bar blah % \$

Regards,
Ikumi Keita