Thank Taco, that worked in the example, of course the general problem stays (thanks to Rik Kabel, too).

But with your suggestion I dicovered a interesting behaviour, see this example:

\showgrid
\setupnote[footnote][before=]
\starttext
\input tufte
\input tufte \footnote{Footnote 1}
\input tufte
\input tufte \dorecurse{35}{Blub or what }\footnote{Footnote 2} That does\footnote{Footnote 3} only\footnote{Footnote 4} work in special cases.
\stoptext

Now Context indeed sets the third and fourth footnote on the second page, but leaves the reference to them on the last line of the first page. This is exactly the behaviour I want in general. Could we force that?

For testing: If we add another footnote in the example above, it fails again - despite of the possibility to just typeset the lines exactly like in the example above, just move the footnotes on the next page, not the references - here might be some logic-mistake at work, because there should be no difference in my opinion between the examples:

\showgrid
\setupnote[footnote][before=]
\starttext
\input tufte
\input tufte \footnote{Footnote 1}
\input tufte
\input tufte \footnote{Footnote extra} \dorecurse{35}{Blub or what }\footnote{Footnote 2} That does\footnote{Footnote 3} only\footnote{Footnote 4} work in special cases.
\stoptext

-- 
Huseyin Özoguz

E-Mail: h.oezoguz@mmnetz.de