Hi, In my project, there is an env-03.tex file that contains this : """""""""""""""""""""""""""""""""""""""""""""""" \startenvironment env-03 \defineenumeration [def] [text={Définition}, headstyle={\bf\feature[+][f:smallcaps]}, width=fit, alternative=left, stopper={.}] \stopenvironment """"""""""""""""""""""""""""""""""""""""""""""""" If I compile, I get this : open source > 4 > 119 > env-03.tex tex error > tex error on line 10 in file env-03.tex: ! You can't use a prefix with `\begingroup' <to be read again> \begingroup \strc_enumerations_command #1->\begingroup \strc_constructions_initialize {#... <to be read again> \20>>1 \dostepwiserecurse ...on \recursedepth \endcsname ##1##2{#4}\global \expanda... <inserted text> ...numerationsub {\v!sub \currentenumerationsub }} \else \let \currentenumera... \define_enumeration ...he \everydefineenumeration \let \currentenumeration \... ... l.10 1 \startenvironment env-03 2 3 \defineenumeration 4 [def] 5 [text={Définition}, 6 headstyle={\bf\feature[+][f:smallcaps]}, 7 width=fit, 8 alternative=left, 9 stopper={.}] 10 >> 11 \stopenvironment 12 Thanks, Fabrice