[NTG-context] missing metapost graphics

Hello, when I try to use MP code in my file, I follow the instructions, but when I compile the file, there is no result whatsoever. Text parts of the document are OK, but there is no trace of the image that should be there. The following is taken directly from metafun manual (page 9) as the minimal ConTeXt example: \starttext \startuseMPgraphic{dummy} fill fullcircle scaled 5cm withcolor red ; \stopuseMPgraphic \useMPgraphic{dummy} \stoptext Well, I get nothing on my setup as well as if I use the online compiler. Therefore I assume that something must be wrong. Could you comment on that? Regards, Matej