[Bug-AUCTeX] 11.86: tex-preview's showlabels option doesn't work with amsmath's multline environment; workaround found

[r6144]

Hello,

I'm using emacs-auctex-11.86-2.fc12.noarch and
tex-preview-11.86-2.fc12.noarch on Fedora 12.

It is a known problem that latex-preview's showlabels option doesn't
work with amsmath's multline environment: the label simply doesn't show
up in the preview of these equations.  This has previously been reported
in http://www.mail-archive.com/address@hidden/msg00653.html quite a
few years ago.  As I rely quite heavily on this option (I think reftex
doesn't use the previews so it isn't as convenient), this bug is rather
annoying.

Using the attached test file, I think I have found the problem.  When
the multline environment is used, the content is expanded twice in
amsmath.sty's \multline@, the first time for measurement only.
address@hidden is thus also called twice, but the second time \next is
equal to address@hidden and processing get skipped.  If I remove this
duplication check, by editing the definition of address@hidden in
prshowlabels.def:

-   address@hidden
+   \iffalse\egroup\romannumeral\else

Labels then show up normally.

Please CC me as I'm not subscribed.

r6144

test-preview.tex
Description: Text Data