Can't seem to get global screen position

[Coises]

It'l probably take a good while, but then it will (hopefully) work at least.

If it’s Windows, see the topics under:

Multiple Display Monitors

especially the example here:

Positioning Objects on a Multiple Display Setup

and the references here:

Multiple Display Monitors Functions

I only have one monitor here, so I can’t tell you if all that works as advertised. I imagine Qt is attempting to use those same functions. (To get an HWND from a Qt window, use QWidget::winId.)