I lost Keyboard focus on both UI and Game Input in Standalone Game

Hey,
I have a little problem with the focus of a widget.
I’m using the ‘Set Input Mode Game And UI’ node to focus on a widget (attached to a Widget Component).
Everything works fine in the viewport, but in ‘Standalone Game’ mode, for some reason, I’m losing the keyboard focus (whether it’s on the player or the widget, no more events respond).
I have to click at least once on the widget to regain keyboard focus.

Does anyone have any ideas as to why the two modes work so differently?

Thanks.