onTapGesure not registering for background of ScrollView

For some reason, the .onTapGesture event won't fire for the background of the ScrollView, but it does fire correctly when applied to the background of a nested VStack view:

    var body: some View {
        ScrollView {
            VStack {...}
            .background(
                Rectangle()
                    .fill(.red)
                    .onTapGesture {
                        print("!!!CLICKED!!!")
                    }
            )
        }
        .background(
            Rectangle()
                .fill(.green)
                .onTapGesture {
                    print("!!!CLICKED!!!")
                }
        )
    }

So when I click the red area, I'm able to see "!!!CLICKED!!!" printed, but when I click the green area, nothing is printed:

ViewLayout image