There appears to be a bug with \startframed. In the following example, 
the instance with no optional argument sets correctly, while with the 
use of an optional argument (even empty []) a whitespace is introduced 
before the text.

    \starttext
    \startframed[]
    Why a space?
    \stopframed

    \startframed
    This is ok.
    \stopframed
    \stoptext

-- 
Rik