math-stc.mkvi:
\unexpanded\def\math_stackers_make_double#top#bottom#category#codepoint#codeextra#text% ... - \ifx\currentmathtext\empty + \ifx\m_math_stackers_text_middle\empty \setbox\scratchboxthree\emptyhbox \else
Thanks for looking into this, Wolfgang. I made this change to math-stc.mkvi in the 2014.05.17 beta, then remade the MkIV format with mtxrun --selfupdate mtxrun --generate luatools --generate context --make Then I ran context on my test file (with 30000 as the \dorecurse count). However, the offset underbraces remain. I'm attaching a image from p. 2128, by which point the offset is 20 or 30pt. I am fairly sure I am running the newly created version, because remaking the format included these lines: open source > 1 > 256 > /home/sanjoy/context/2014.05.17-beta/tex/texmf-context/tex/context/base/math-stc.mkvi loading > ConTeXt Math Macros / Stackers close source > 1 > 256 > /home/sanjoy/context/2014.05.17-beta/tex/texmf-context/tex/context/base/math-stc.mkvi and the log output from running the minimal.tex shows that the the fmt is indeed dated 2014.7.3: mtx-context | run 1: luatex --fmt="/home/sanjoy/context/2014.05.17-beta/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/luatex/cont-en" --jobname="minimal" --lua="/home/sanjoy/context/2014.05.17-beta/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/luatex/cont-en.lui" --no-parse-first-line --c:currentrun=1 --c:fulljobname="./minimal.tex" --c:input="./minimal.tex" --c:kindofrun=1 --c:maxnofruns=8 "cont-yes.mkiv" This is LuaTeX, Version beta-0.79.1 (TeX Live 2014/dev) (rev 4972) \write18 enabled. open source > 1 > 1 > /home/sanjoy/context/2014.05.17-beta/tex/texmf-context/tex/context/base/cont-yes.mkiv ConTeXt ver: 2014.05.17 23:46 MKIV beta fmt: 2014.7.3 int: english/english -Sanjoy
