Looking at that code, it’s pretty much what I was already doing - except I hadn’t set an input pre-processor and I’m not doing the same things with the window/viewport.
I think the main issue I’m having is that the WidgetComponent’s window/viewport is not getting the events, either the mirror window is or the VR viewport itself is.
Anyway, thanks ! I’m going to see if setting up my input preprocessor and maybe doing something hacky with the WidgetComponent’s window/viewport does what I need.