Multiple monitor embedded system

[Mike Peterson <mikepe pacbell net>]

I am trying to use GTK for an embedded system.
(FYI, it is a gas pump...)

It always has 2 small 800x480 monitors, and sometimes has a larger 
1280x1024 monitor for development.
I have configured X correctly, and have a "screen" that is 2080x1024.

I need to create two main windows, one for each of the small displays.
Each small display needs to be completely filled with its window.

I am currently using GTK_WINDOW_POPUP, and it seems to work.
When I try to use GTK_WINDOW_TOPLEVEL, it appears that all attempts to 
move the windows to the correct place on the virtual screen are ignored.

Any ideas?