I have two graphics cards, but with docking station it is three drivers (display adapters).
I checked if cards behave same on dock, so small update:
Without docking station I'm able to run SFML app on both graphic cards.
With docking station I'm able to run SFML app only on integrated card (Intel HD Graphics 630), but not on hi performance (NVIDIA GeForce GTX 1060).
Not sure in what context display adapter for dock stations works (Kensington USB3.0 Video Dock).
All drivers are updated.
I had similar issue (not able to run on hi-perf card when screens are connected by docking station) for one game in beta, but after official release it was working properly.
If its bug in integrated card driver it should not work on both (dock and without dock)
If its bug in hi-perf card it should not work on both (dock and without dock)
If its bug in dock station it should not work when dock station is plugged in.
But it don't work only on dock + hi-perf.
From your perspective it seems that issue is in driver and there is nothing what can be done in SFML?
How can I check with what driver SFML communicating is? It's strange that after connecting docking station (with two screens) Hi-Perf GPU driver start working in different way.