[NTG-context] math error in ConTeXt?

Of these two variants the second works. The first gives as error an old enemy: the \Umathquad error % gives an error: \startsetups[test] $\displaystyle a=1 $ \stopsetups \setup[test] \stoptext % works: \starttext $$\displaylines{a=1\cr b+c+d=3\cr}$$ \stoptext ConTeXt ver: 2012.01.16 18:33 MKIV ! Math error: parameter \Umathquad\displaystyle is not set. \8>:test #1->$\displaystyle a=1$ Why this error? Hans van der Meer