Hi,
For my book, the header for each chapter should be like the attached image. I
don't know if I am using the best method, but the result looks like what I
want. Nevertheless, I am having a problem.
I don't understand why the first chapter is not numbered while the second
is with number 1 etc.
Thanks.
Fabrice

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\definecolor[MyColorA][r=0.8784, g=0.8784, b=0.8784]

\defineframedtext
          [FramedText]
          [
            offset=0.6em,
            style=,
            toffset=\lineheight,
            background=color,
            backgroundcolor=MyColorA,
            foregroundstyle={\switchtobodyfont[11pt]},
            align={left, broad},
            frame=off,
            width=\textwidth,
          ]

\setuplabeltext
     [en]
     [chapter=CHAPITRE]


\setuppagenumbering
  [alternative=doublesided,location=]


\unexpanded\def\HeadTitle#1#2%
   {
     \FramedText{{\cap\labeltext{chapter}}\space#1
      \\
     \bfc#2}
   }

\unexpanded\def\processheadnumber#1%
   {\getmarking[chapternumber]}

 \setuphead
   [chapter]
   [style=\bfd,
    align={flushleft,broad},
    numbercommand=\processheadnumber,
    command=\HeadTitle]


\starttext
\startchapter [title={La récurrence}]
  \startsection[title={Le principe de récurrence}]
    \input knuth
  \stopsection
  \startsection[title={Le raisonement par récurrence}]
      \input knuth
  \stopsection
  \startsection[title={Récurrences fortes}]
    \input knuth
  \stopsection
   \startsection[title={Exercices corrigés}]
    \input knuth
  \stopsection
\stopchapter
\startchapter [title=Combinatoire-Dénombrement]
   \input knuth
\stopchapter
\startchapter [title=Suites]
  \input knuth
\stopchapter
\stoptext
####################################