Hello,
how to add the hairline (or a kind of the horizontal rule) under the header area?
\setupbackgrounds[header][text][bottomframe=on]
\setuplayout[header=1cm,headerdistance=1cm]
\starttext
\dorecurse{12}{\input knuth\par}
\stoptext
\setupheader[text][after=\thinrule]
\setuplayout[header=1cm,headerdistance=1cm]
\starttext
\dorecurse{12}{\input knuth\par}
\stoptext