Description
When a body has two displays (VDD as primary at 0,0 and a secondary physical display at 1080,0), Unreal Engine opens its window at the position saved in GameUserSettings.ini rather than on the primary VDD display. The UE launch args registered in Sunshine are `-ResX=1080 -ResY=1920 -windowed -ForceRes` but do not include `-WinX=0 -WinY=0`. If a previous session saved a window position on the secondary display, the next session opens there instead of the VDD. Sunshine captures only the VDD (offset 0,0), so the stream shows the kiosk overlay while Mercator renders at full GPU on the secondary display. Fix: add `-WinX=0 -WinY=0` to the UE launch args in `streamResolution` (pkg/provider/experiences.go lines 48-54) so the window position is always forced to (0,0) regardless of saved settings.
Observed on: fluffy-dumpling-87 (node-11da9ea3), bxl1-test-2 district, cloud-seven venue.
Severity: medium (requires stream restart + manual GameUserSettings.ini deletion to recover).