[texhax] Latest updates/AMS LaTeX making variable sized delimiters (parentheses/brackets/braces) disappear?

[Barbara Beeton]

regarding the problem with large delimiters,

    [...] It was yhmath playing up. Removed it and no issues.
    
    Wonders what was the problem though. I've had yhmath loaded for a long time and nothing wrong has occurred until today.

    [...]

    Sorry - I should add - it doesn't work in the gather* and aligned environments.

    It does work in inline math!

    [...]

    Since the last update, whenever I use $\left(x^2\right)^2$, the variable sized parentheses/braces/brackets disappear, [...]

    [...]

    Has anyone else seen this phenomenon? In my almost 10 years of using MiKTeX, there has not been an issue like this ever! This appears in the DVI as well as the PDF output (dvi -> ps -> pdf)

    I'm on the latest packages available from the MiKTeX site.

    [...]

in may 2010, the package formerly known as
"amslatex" was split in two -- "ams classes"
and "amsmath".  this split was sometime later
recognized and made at ctan; the distinction
was already built into tex live.  however,
miktex at some point noticed that amslatex
was no longer present under that name on ctan
and assumed that it had been withdrawn, was
obsolete, or ... and apparently rearranged the
distribution.  (not being a miktex user, i'm
not familiar with the details, but the problem
was reported in at least one tex forum:
  http://tex.stackexchange.com/questions/96778/

since amsmath itself hasn't been updated since
version 2.13, dated 2000/07/18, i suspect the
problem is somewhere else, but i can't guess
exactly where.  however, i don't think the
problem as described should happen, so i would
really like to look at a test file (with the
yhmath package included) to see if the problem
can be tracked down.  some ams authors use the
package for larger forms of some diacritics,
but this problem has never been reported, and
if the source can be identified, that would
be useful.  you can send the test file(s) to
tech-support (at) ams.org.  thanks.
						-- bb