[NTG-context] Nested sections in interface=xp?

I'm interested to know whether nested sections are supported in the new structure code (strc-*)? Using the following to test, I don't get a section and subsection, but rather two sections. The log file notes a "missing \stopsection". \starttext \startsection{Section} \input tufte \startsection{Subsection} \input knuth \stopsection \stopsection \stoptext Am I missing a setup command somewhere in the new structure code that enables nested sections? Thanks, Kevin