Platform independent popup menus can also be realized using pure G.
Try
the attached example (LabVIEW 7.1, but would work in older versions
too).
My simple example so far does not support nested menus but there
are examples for that, too.
See, e.g., the discussion at the
OpenG-forum:
http://forums.openg.org/viewtopic.php?t=31&start=0&postdays=0&postorder=asc
Regards
Arno