The display I am using is set to resolution 1440x5120 - and I can confirm that it is at this resolution. This is on a Windows 10 system.
I open a window to the display and fill it with gray, with:
win = visual.Window([5120,1440],
But the window on-screen stops short, 10 lines from the bottom. I see a yellow border line (1 pixel) to the window, and below that I see the background image for that display.
If I call for a window 1450 pixels high, I get the same result. Why might it be stopping short of filling the display?