There is the following problem on code that did work around july 2007, but no longer under the current context version (2008-03-11). Define a description, I did: \definedescription[answerblock][% \c!margin=\v!no,\c!location=\v!left,% \c!headstyle=\@@exmintrostyle,\c!style=\@@exmstyle,% \c!before=,\c!inbetween=,\c!after=,% \c!hang=\@@exmhang,\c!width=\questionblockwidth,% \c!text=\placeanswerstart] Typeset with this description inside the following macro: \def\shortanswer#1\par{% \par % be sure to end paragraph here \answerblock{}% % {} needed here in description call \ifanswers #1\else\dotfill\strut\fi % <<<<<< crashing on this if \par % final \par of description ... \par } The above code crashes with: ! Incomplete \ifx; all text was ignored after ... After some detective work in which Wolfgang Schuster had a large share and has found the most elegant workaround, the addition of a \relax just after the description call prevents the error: \def\shortanswer#1\par{% \par % be sure to end paragraph here \answerblock{}% % {} needed here in description call \relax % <<<<<<<<<<<<<<<<< \relax prevents crash on if \ifanswers #1\else\dotfill\strut\fi \par % final \par of description ... \par } The way \relax stops the error reminds me of the \relax that one places after a number in order to separate that from the code following. I did compare core-des.tex, both the last version and the archived from 2007-04-17. But I must admit, I did not succeed finding a clue among the differences about what could have happened. The code is a bit too intricate to just jump in and pinpoint the culprit -- at least for me. Allthough Wolfgang's workaround saves the day, I feel this problem deserves solving inside ConTeXt, not outside it. Someday somewhere another person will stumble on the same problem -- a situation that can and should be avoided, in my view. Therefore I explain the problem here as fully as possible hoping someone knowledgeable with descriptions <<we might need to fall back to Taco or Hans>> will find the best remedy. Hans van der Meer