Hi Wolfgang,
Pablo's solution works, but I tried yours without success. Here are the main lines of my project
%%%% begin product
\startproduct[terminale-manual]
\project[terminale-environment]
\startdocument
\startfrontmatter
...
\stopfrontmatter
\startbodymatter
\component[terminale_recurrence]
...
\stopbodymatter
\stopdocument
\stopproduct
%%%% end product
%%%% begin project
\startproject[terminale-environment]
\environment[terminale-style]
...
\stopproject
%%%% end project
%%%% begin component
\project[terminale-environment]
\startcomponent[terminale_recurrence]
...
\endcomponent
%%%% end component
%%%% begin environment
\startenvironment[terminale-style]
...
\startsetups [section:chapter]
\setuphead
[chapter]
[align=flushright,
textcommand=\groupedcommand{\blank[medium]}{},
numbercolor=darkgray,
textstyle=ChapterTextStyle,
numberstyle=ChapterNumberStyle,
before=\startChapterFrame,
after=\stopChapterFrame,
header=high]
\stopsetups
\startsectionblockenvironment [bodypart]
\directsetup{section:chapter}
\stopsectionblockenvironment
\doifmode{*component}{\directsetup{section:chapter}}
...
\endenvironment
%%%% end environment