I have the following document:
\setupheader[
  after={\startalignment[center]\hairline\stopalignment},
  style={\switchtobodyfont[9pt]},
]

\setuplayout[
  footer=0mm,
  header=10mm,
]

\setupheadertexts[]
\setupheadertexts[Documentation for product XYZ –concept–]
                 [version: 2001-07-19]

\starttext

Just some text to fill the document.

\stoptext


I would expect the hairline to be at the  same place as the text of the
document, but instead it is completely left aligned. What am I doing wrong?

-- 
Cecil Westerhof