Columns and backgrounds problem

[Matthias Weber <matweber@indiana.edu>]

Hello,

I am trying to use backgrounds in columns. Typically, the background  
runs into the other column as the following example.

Is this a limitation, or am I doing something wrong?

Any help is appreciated.

Matthias




\setupcolors[state=start]
\setuppagenumbering[location=]
\setupbodyfont[12pt]

\definecolor[myframecolor][r=.0,g=.5,b=.6]
\definecolor[myheadcolor][r=.0,g=.5,b=.0]
\definecolor[myemcolor][r=.6,g=.1,b=.5]
\definecolor[textcolor][r=.2,g=.02,b=.3]



\definecolor[thmcolor]
	[r=.94,g=.94,b=.9]
	
\definetextbackground
[thmbackground]
[backgroundcolor=thmcolor,
%corner=round,
before=\blank,
after=\blank,
leftoffset=5pt,
rightoffset=5pt,
topoffset=5pt,
bottomoffset=5pt,
frame=on,
framecolor=darkblue,
location=paragraph,
color=darkblue]


\defineenumeration
[theorem]
[before={\starttextbackground[thmbackground]},
after={\stoptextbackground},
text=Theorem,
way=bysection,
location=hanging,
letter=rm]


\setuppapersize[letter][letter]


\starttext


\startcolumns[n=2]

\input tufte

\starttheorem $1+1=2$
\stoptheorem

\input tufte

\starttheorem $1+1=2$
\stoptheorem

\input tufte


\stopcolumns

\stoptext