how to force display refresh of drawing area?

[明覺 <shi minjue gmail com>]

I have a gtkglextmm app which displays a rotating 3d surface. On the
same machine I installed a debian linux and a windows vista, the app
displays smoothly in debian, but in vista, there seems to be some
caching of the display, which means, if I add many cout<<"string" in
my application, the 3d display area gets freshed when the cout strings
reach a certain amount, but if I don't add those cout in my app, the
3d surface will not appear untill I switchs tab pages(the 3d area is
in one of a tab page). So I guess there must be some display cache in
the windows system, how could I force flushing the display so that my
3d surface can be displayed normally? thanks

-- 
我的操作系統是Gnu/Linux Debian/gNewSense Gnome Mozilla Gmail/Evolution
Gtkmm/Gtkglextmm Scim Totem Pidgin.