Widget Interaction Component (Mouse) not working in VR

Since Unreal 4.17, Widget Interaction Components don’t trigger any hits in VR mode, if their source is set to “Mouse”. (Tried with Oculus CV)
I have tried with a fresh project that did work fine in 4.16, here are the steps to reproduce:

  • Create a new project based on the FPS / C++ template
  • Add a Widget Interaction Component to the FirstPersonCharacter, leave the defaults but set “Interaction Source” to Mouse. (optionally enable Debug)
  • Create a WidgetBlueprint, remove its Canvas and add a Button. Add some hover effect to the Button (e.g. Tint color).
  • Create an Actor Blueprint with a Widget Component. Set its widget class to the new widget and place it in the scene.
    Play in VR mode → works in 4.16, when upgrading the project to 4.17 or creating it in 4.17, no hover effect is visible and the debug gizmo does not display.

I noticed that when playing a cooked build, the cursor appears but still seems to be a bit offset, depending on the viewport size. Might this be related to UE-47210? It still requires a huge testing effort for every UI change in VR (i.e. creating a build).