@Devolution.exe I’m having big troubles with this still. I have two monitors, where the primary one is a high-DPI model. My issue, in case you (or someone) else discovers a solution:
It is exactly as you describe:
I can start the application perfectly fine on the primary monitor. But if I start on the secondary monitor the mouse coordinates are just wrong. If I switch monitor then sometimes this also messes up the mouse coordinates when switching to the secondary monitor.
There are quite a few variables involved here: UGameUserSettings, the UGameViewportClient, FSlateApplication, the GEngine->GameViewport, and I’m not quite sure where to look.
Any help is appreciated. And I will post here if I discover a solution.