Using: SWI-Prolog (threaded, 64 bits, version 8.1.24) on Windows 10.
One minor problem when using SWI-Prolog with Windows 10 and using multiple monitors as an extended display is that when I use SWI-Prolog tools such as GUI tracer (gtrace) with the tracer showing on a monitor other than the primary monitor, if I use the mouse to select a menu option the sub-menu will appear on the primary monitor at the left edge.
e.g gtrace running on Monitor 1, sub-menu will appears on Primary Monitor so I have to turn 90 degrees to the right to find the sub-menu.
-------------- -------------- -------------------
| Monitor 1 | | Monitor 2 | | Primary Monitor |
| | | | | |
-------------- -------------- --------------------
The fix might be as simple as allowing a negative number for the X position of the sub-menu.
There is no need to rush a fix for this as I have been using it this way for many months, it is that every now and then I forget that I need to look right.