I’m working on a SwiftUI application for macOS and am encountering an issue where a .sheet modal that uses .ultraThinMaterial is not blending as expected with the underlying background. I want the modal to have a semi-transparent look that allows the background color to show through, but currently, it appears opaque.

Here’s the relevant part of my code:

import SwiftUI

struct ContentView: View {
    @State private var showModal = false

    var body: some View {
        ZStack {
            Color.blue
                .edgesIgnoringSafeArea(.all)

            Button("Show Modal") {
                showModal.toggle()
            }
            .buttonStyle(.bordered)
            .sheet(isPresented: $showModal) {
                ModalContentView()
            }
        }
    }
}

struct ModalContentView: View {
    var body: some View {
        ZStack {
            Text("This is a modal view")
                .font(.title)
                .foregroundColor(.white)
        }
        .frame(width: 300, height: 200)
        .background(.ultraThinMaterial)
        .cornerRadius(12)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

I expect the modal to show the blue background slightly through its content due to the .ultraThinMaterial, but it does not blend at all. How can I adjust the modal or its background to achieve the desired blending effect with the color set in the ContentView?

Any suggestions or insights would be greatly appreciated. Thank you!