Hi Ikumi,

>
> The fundamental origin of the problem is that RefTeX presumes that it
> always works in the buffer associated with files. In other words, RefTeX
> pays no attention to non-file buffer. (I have such impression, skimming
> over the RefTeX code. Please correct me if I'm wrong.)
>

This has also been my understanding (although I stopped using RefTeX
years ago, basically for this reason).

>>>>>> "Paul D. Nelson" <ultrono@gmail.com> writes:
>> The attached patch addresses the issue for me.  Thoughts?
>
> I have basically the same idea, but I think such partial treatment
> inctroduces inconsistent internal state of RefTeX and can be potential
> problems. Rather I propose to wrap the whole RefTeX management
> part in amsmath.el by (when buffer-file-name ... ). In addition, we
> should turn off RefTeX mode in `TeX-mode-cleanup' like
>   (unless buffer-file-truename
>     (if (bound-and-true-p reftex-mode) <-- addition
>       (reftex-mode -1))                <-- addition
>     (TeX-update-style))
> to avoid inconsistency.
>

Something like the attached, I guess?  There are other uses of "reftex-"
in style/, so I guess something similar should be done for all of them?

Thanks, best,

Paul