Hello,
I can not adjust the bottom line of my header even after playing with
location= and boffset.=
Thank you.
Fabrice

\definelayout
    [first]
    [topspace=1cm,
     backspace=3cm,
     cutspace=3cm,
     leftmargin=.75cm,
     leftmargindistance=.5cm,
     rightmargin=1.25cm,
     rightmargindistance=1cm,
     header=1cm,
     headerdistance=1cm,
     footer=1cm,
     footerdistance=1cm,
     width=middle,
     height=middle,
     location=middle]

  \setuplayout
    [topspace=1cm,
     backspace=3cm,
     cutspace=3cm,
     leftmargin=.75cm,
     leftmargindistance=.5cm,
     rightmargin=1.25cm,
     rightmargindistance=1cm,
     header=\zeropoint,
     headerdistance=1cm,
     footer=1cm,
     footerdistance=1cm,
     width=middle,
     height=middle,
     location=middle]

  \definelayout
    [last]
    [first]

  \setupbackgrounds
    [header]
    [text]
    [frame=off,
     topframe=off,
     bottomframe=on,
     framecolor=,
     rulethickness=1pt]

  \defineframed
    [headerframed]
    [frame=off,
     height=fit,
     width=fit]

    \startuseMPgraphic{framewithshadow}
      path p;

p:=origin--(1.05*OverlayWidth,0)--(1.05*OverlayWidth,1.05*OverlayHeight)--
    (0,1.05*OverlayHeight)--cycle;
      fill p shifted (3,-3);
      fill p withcolor 0.8white;
      draw p;
      setbounds currentpicture to p;
    \stopuseMPgraphic

    \defineoverlay[framewithshadow][\useMPgraphic{framewithshadow}]

    \definecolor[ColorA][0.8(white)]

    \startsetups [headertext]

  \setupheadertexts
     [{\startframed [headerframed]
     [foregroundstyle=bold,background=framewithshadow]
     \getvariable{headertext}{title}
n\high{o}\,\getvariable{headertext}{number}
       \stopframed}]

  \setupheadertexts
     [{\startframed [headerframed]
     [align=flushleft,foregroundstyle=]
     Lycée LA SALLE, Lille\\
     \getvariable{headertext}{location}
       \stopframed}]

     [{\startframed [headerframed]
       [align=flushright,foregroundstyle=]
   \date[d=\getvariable{headertext}{day},m=\getvariable{headertext}{month},
             y=\getvariable{headertext}{year}] [D,month,{ },year]
        \stopframed}]

  \stopsetups

  \setvariable{headertext}{set}{\directsetup{headertext}}

  \setvariables
    [headertext]
    [title={Corrigé du devoir maison},
     number={1},
     day={22},
     month={10},
     year={2019},
     location={Secondes GTE-GTF},
     time={}]

 \starttext

  \input knuth

 \stoptext