I have an installation with 1 control screen (1920x1200) and 5 HD projectors, usually at 1280x720. This puts my furthest screen coordinate at 8320...but....using the 'rect' or 'size+pos' attributes: I cannot get past 8200! This leaves a blank spot on the edge of my 5th screen. If I change to a higher resolution, like 1080, I am still stuck with the 8200 limit, except now its in the middle of my 4th screen. jit.displays shows all the screen coordinates correctly.
If I manually try to move the left edge higher than 8200 I can see a sliver moving on the screen, but as soon as I move the right edge it disappears.
As a work around, I have put the 5th screen on its own context and then used full_screen, which does work, but I take a major hit in frame rates. It will not be practical at higher resolutions. I've tried this with as many as 4 graphic cards together and as few as 2; still the same.
Any ideas appreciated.