header - underline

[Radim Uchac]

Hi,
I would like to underline headers on all pages. I tried to do:

\setuppagenumbering[location=]
\setupheader[text][style=tfx,after=\hairline]
\setupheadertexts[text][][pagenumber][][pagenumber]

but now hairline starts from left border of paper and not from 
left border of text area. Any idea?
thanks radim