[NTG-context] Mark off boxes

I am trying to create a form which will use check boxes in it. I tried to use the \bigsquare character for the check box and put in in an itemize list. The \bigsquare character, however does not display however in the itemized list, but will display by itself. What do you normally do for check boxes? Here is a minimal example: ----------------------------- \definesymbol[5]{\bigsquare} \starttext This is a big square: \bigsquare \startitemize[5] \item Choice a does not have a check box. \item Choice b also does not have a check box. \item Not really a choice. No checkbox (bitsquare) here either. \stopitemize \stoptext ----------------