Hans—there are still some odd failures in hyperlinking between components.
At least in the following product file with two components, some links work (\reference), some only sometimes (\at) and others never (\in). The problem seems to be with labels.
\startproduct LinkTest
\setupinteraction[state=start]
\component Test01
\component Test02
\stopproduct
\startcomponent Test01
\product LinkTest
\reference[startknuth]{}\input knuth
\page
\input knuth\reference[endknuth]{}\footnote[knuth]{A note.}
\section[new]{a title}
\input ward
\page[makeup]
\stopcomponent
\startcomponent Test02
\product LinkTest
\type{\reference}, pp.\ \at[startknuth]–\at[endknuth]
\type{\in} using a label: \at[knuth]n\in[knuth] as well as \at[new] (ref to section).
\page[makeup]
\stopcomponent
The links to labeled items work within a single document:
\startcomponent Test03
\setupinteraction[state=start]
\section[new]{A title}
text\footnote[test]{text.}
\page
reference to note: \at[test]n\in[test]
reference to section: \at[new]
\page[makeup]
\stopcomponent
Alan