OnMouseButtonDown only works in outermost UUserWidget?

I am having trouble getting OnMouseButtonDown_Implementation() working on a UserWidget I have inside of another UserWidget.

The function is simple but only triggers on the outermost Widget, is there a way around this?

FEventReply URoMPlayerMenuWidget::OnMouseButtonDown_Implementation(FGeometry MyGeometry, const FPointerEvent & MouseEvent)
	FEventReply reply = Super::OnMouseButtonDown_Implementation(MyGeometry, MouseEvent);

	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("URoMPlayerMenuWidget::OnMouseButtonDown_Implementation!"));

	return reply;

What I am basically trying to do is replicate this blueprint (which works great) in C++.

any chance you managed to find solution?