Thanks, Wolfgang, that indeed does the trick.

A related question.  I've noticed that global `whitespace' setup is not recognized by `makeup' environment, i.e.

\setupwhitespace[line]

\definemakeup
[abstractpage]

\startabstractpagemakeup

% `whitespace' is definitely not `line'.

\stopabstractpagemakeup

The trivial and ugly solution is to

\definemakeup
[abstractpage]

\startabstractpagemakeup

\setupwhitespace[line]

% `whitespace' is definitely `line'.

\stopabstractpagemakeup

However, I would prefer

\setupmakeup[
  commands={%
    \setupwhitespace[line]%
  },
]

but it has no effect too.  I would like to know why and if there is a alternative?

By the way, the similar setting

\setupmakeup[
  commands={%
    \setupinterlinespace[line={4.2ex}]%
  },
]

does have an effect.  Once again, why?  What's the difference in this case?

Regards,
Alexander