This surely works ok for "top left". But how can I guarantee that "top right" has its *top right* corner in the position? I would have to calculate the coordinates manually (depending on page site, "top right text" dimensions etc).
Yes, AFAIK the mechanism does not support this now (and I do not know, if it sometimes will do -- it seems to me it is a relatively old part of ConTeXt and Hans himself recommends you the layers :-). Anyway, you would have to count positions and coordinates manually. But there is always a way using generic TeX here: \position(40,1){% \hbox to 0pt{% \hss \vbox to 0pt{ -- a material to typeset or display -- \vss } } Of course, this solution does not take into account all of ConTeXt dependent (and very convenient and pretty) features like grid fitting etc. It is a thing of your needs. Have a nice day, Martin