Dear ConTeXt hackers,
did you look at the options described in details.pdf? maybe grid=page will help;
OK, yesterday I have played with my problem a bit and here is a testfile. I "need" grid=top for the extra distance between the previous paragraph and the sectionheading. So grid=page can only be an option if the section starts at the first line on a page. (Which indeed solves my problem; just saying \setuphead[somehead][grid=top] for the problematic section headings works fine, but this is ... well I guess I don't have to explain).
another option is to set the topskip to strutheight (something \setupinterlinespace[top=.72])
Hmm, no effect I can see. I don't remember why I used the \definesection stuff. -------------------------------------------------- \showgrid \definesection [foo] \setupsection [foo] [previousnumber=no] \definehead [somehead] [section=foo] \setuphead [somehead] [grid=top] \setuplayout[width=fit, grid=yes, height=\dimexpr(21\lineheight+\footerheight+\headerheight), ] \starttext \dorecurse{4}{% \somehead{Dummy} \input tufte } \stoptext