Positioning tag adding space before a chapter

["Paul Jones" <shagreel@gmail.com>]

I am using \StartPos and \StopPos to determine where text is
positioned in the output document.  This works very well except that
when it is placed before the first chapter in the bodymatter it adds a
blank page.  All of the other chapters are fine.  Is there some way
for me to make this not happen?  I don't understand everything inthe
StartPos def.  But if I remove the \StartPos from before the first
chapter the blank page is not there, but I need that positioning
information.   I will be greatful for any help.

Paul

% output=pdftex
\let\CurrentPos\empty
\def\StartPos#1{\pushmacro\CurrentPos\edef\CurrentPos{flpos:#1}\dontleavehmode\bpos\CurrentPos\ignorespaces}
\def\StopPos{\removeunwantedspaces\epos\CurrentPos\popmacro\CurrentPos}
\starttext
\startfrontmatter
\setuppagenumbering[alternative=doublesided]
\stopfrontmatter
\startbodymatter
%\chapter{testing}\StartPos{p:31:1}Here is the text to drop a photo
into.\StopPos
\StartPos{s:31}\chapter{Another Section}\StartPos{p:31:1}Here is the
text.\StopPos\StopPos
\StartPos{s:32}\chapter{Another Section}\StartPos{p:32:1}Here is the
text.\StopPos\StopPos
\stopbodymatter
\stoptext