I want topspace=bottomspace=2cm
It works for topspace but not for bottomspace

How to do ?

Thanks

Fabrice

\setuplayout
  [header=26pt,
   headerdistance=25pt,
   backspace=2cm,
   width=middle,
   topspace=\dimexpr 2cm-\headerheight-\headerdistance\relax,
   footer=16pt,
   bottomspace=\dimexpr 2cm-\footerheight-\footerdistance\relax]