[texhax] Bad effect when using xetex together with color

[Philip Taylor]

David Carlisle wrote:
>
> So the behaviour is as documented and hasn't changed since this plain
> tex wrapper was released in 1995.

Well, that last part is interesting, because when I first tested Rudolfo's code I could not replicate his results; I then saw I was using XeTeX/2017 with TeX-Live/2014.  When I switch to XeTeX/2018 with TeX-Live/2018, I could replicate his results and avoid them by using \begingroup / \endgroup as reported.  So /something/ appears to have changed in this area between 2014 and 2018.

** Phil.