SwiftUI中的演示模式不会取消工作表(/U)？

struct ContentView: View {
    @State private var showSheet = false
    
    var body: some View {
        Button("Show Sheet") {
            showSheet = true
        }
        .sheet(isPresented: $showSheet) {
            SheetView()
        }
        .onAppear {
            // 进入演示模式
            #if DEBUG
            if CommandLine.arguments.contains("-demoMode") {
                showSheet = true
            }
            #endif
        }
    }
}

struct SheetView: View {
    @Environment(\.presentationMode) var presentationMode
    
    var body: some View {
        VStack {
            Text("This is a sheet")
            Button("Close") {
                presentationMode.wrappedValue.dismiss()
            }
        }
    }
}