[NTG-context] \AA cannot be uesed in math mode?

[fdu.xiaojf at gmail.com]

Hi,

I want to get a sign of angstrom in an math formula, here is my example:
%--------------------
\starttext
$\AA$
\stoptext
%--------------------
and the error message:
%--------------------
systems         : begin file d at line 1
! Please use \mathaccent for accents in math mode.
\dochar #1->\char
                  #1\relax
\dobuildtextaccent ...{\let \char \normalaccent #1
                                                  \let \char \normalchar #2}
l.2 $\AA
        $
%--------------------

I can use \AA successfully in text mode.
Is there anything wrong with my tex file?

Thanks.