bug?: interaction between columns and background

["Mojca Miklavec" <mojca.miklavec.lists@gmail.com>]

Hello,

When I place a graphic in the bacground and switch columns on, the
background gets shifted for some reason.

I hope that the problem will be evident from this example (since it
behaves in a pretty random way - sometimes it's OK and sometimes it's
pretty much shifted to the left).

(Using ConTeXt version 2006.08.30 9:28)

\startuseMPgraphic{TitleGraphic}
draw unitsquare xyscaled (\overlaywidth-5mm,\overlayheight-5mm);
\stopuseMPgraphic

\defineoverlay [TitleGraphic] [\useMPgraphic{TitleGraphic}]
\setupbackgrounds[page][background={TitleGraphic,page}]

\starttext

\startcolumns[n=3]
\dorecurse{3}{\input tufte $$a^2+b^2=c^2$$}
\stopcolumns

\stoptext

Thank you,
    Mojca