SwiftUI Picker with Enum Source Is Not Enabled

I'm trying to understand the new SwiftUI picker style, especially with data from a source other than an array. I have built a picker with an enum. I first made a simple app with only the picker and associated enum. This works as expected.

Strangely, when I copy and paste that code into another app with other controls in the form, the picker seems to be inactive. I see it, but cannot click it.

Here's the first app (the picker works):

struct ContentView: View {

    @State private var selectedVegetable = VegetableList.asparagus

    var body: some View {
        NavigationView {
            Form {
                Section {
                    Picker(selection: $selectedVegetable, label: Text("My Vegetables")) {
                        ForEach(VegetableList.allCases) { v in
                            Text(v.name).tag(v)
                            //use of tag makes no difference
                        }
                    }
                }
            }
            .navigationBarTitle("Picker with Enum")
        }
    }
}

enum VegetableList: CaseIterable, Hashable, Identifiable {
    case asparagus
    case celery
    case shallots
    case cucumbers

    var name: String {
        return "\(self)".map {
            $0.isUppercase ? " \($0)" : "\($0)" }.joined().capitalized
    }
    var id: VegetableList {self}
}

Here's the app with other controls (picker does not work).

struct Order {
    var includeMustard = false
    var includeMayo = false
    var quantity: Int = 1
    var avocadoStyle = PepperoniStyle.sliced
    var vegetableType = VegetableType.none
    var breadType = BreadType.wheat
}

struct OrderForm: View {

    @State private var order = Order()
    @State private var comment = "No Comment"
    @State private var selectedVegetable = VegetableType.asparagus
    @State private var selectedBread = BreadType.rye

    func submitOrder() {}

    var body: some View {
        Form {
            Text("Vegetable Ideas")
                .font(.title)
                .foregroundColor(.green)
            Section {
                Picker(selection: $selectedVegetable, label: Text("Vegetables")) {
                    ForEach(VegetableType.allCases) { v in
                        Text(v.name).tag(v)
                    }
                }
                Picker(selection: $selectedBread, label: Text("Bread")) {
                    ForEach(BreadType.allCases) { b in
                        Text(b.name).tag(b)
                    }
                }
            }

            Toggle(isOn: $order.includeMustard) {
                Text("Include Mustard")
            }

            Toggle(isOn: $order.includeMayo) {
                Text("Include Mayonaisse")
            }

            Stepper(value: $order.quantity, in: 1...10) {
                Text("Quantity: \(order.quantity)")
            }

            TextField("Say What?", text: $comment)

            Button(action: submitOrder) {
                Text("Order")
            }
        }
        .navigationBarTitle("Picker in Form")
        .padding()

    }
}

enum PepperoniStyle {
    case sliced
    case crushed
}

enum BreadType: CaseIterable, Hashable, Identifiable {
    case wheat, white, rye, sourdough, seedfeast
    var name: String { return "\(self)".capitalized }
    var id: BreadType {self}
}

enum VegetableType: CaseIterable, Hashable, Identifiable {
    case none
    case asparagus
    case celery
    case shallots
    case cucumbers
    var name: String {
        return "\(self)".map {
            $0.isUppercase ? " \($0)" : "\($0)" }.joined().capitalized   
    }
    var id: VegetableType {self}
}

Xcode 11 Beta 7, Catalina Beta 7 There is no behavior difference between Preview and Simulator .I must be missing something simple here. Any guidance would be appreciated.