hi, i have the following setup:

\usemodule[simplefonts]
\setmainfont[Cambria]
\setsansfont[Ubuntu]
\setmonofont[Envy Code R][regularfont=envycoder]
\setmathfont[Cambria]

\setuphead[section][style={\ss\bfb}]

\starttext
\section{Wat? $y=x^2$}
\stoptext

why is the math in the header typeset in computer modern instead of ubuntu
and how do i fix it?

PS: preferrably it should be bold, too. there is a wiki page, “Bold Math in
Section Titles <http://wiki.contextgarden.net/Bold_Math_in_Section_Titles>”
but it doesn’t explain how to do it with simplefonts.