[NTG-context] No pagenumber on first page

Hi folks, if I use this:     \setupheadertexts[]     \setuptexttexts       [margin]       [] [\unframed[align=middle,width=\outermarginwidth]{\pagenumber}] [\unframed[align=middle,width=\outermarginwidth]{\pagenumber}]       []     \starttext     \dorecurse{50}{\samplefile{tufte}\par}     \stoptext How can I avoid the pagenumber on the first page? Thank you very much for your help! Greetings Thomas