Content of SwiftUI Popover Out-of-Focus

I noticed that in my current macOS SwiftUI App setup in which a popover occurs when a button is pressed, the content of the popover appears a little pale:

In contrast, when I click into the popover, the content gets its correct color:

This seems to be corrected when I get rid of the HStack which embeds the button and the Image. Here is the code that generates the app:

import SwiftUI

struct ContentView: View {
    @State var showPopup: Bool = false
    @State private var users: [User] = [User(name: "Peter"), User(name: "Paul"), User(name: "Martha")]
    @State var selectedUserIndex: Int = 0
    
    var body: some View {
        NavigationView {
            List {
                HStack {
                    Button(action: {
                        self.showPopup.toggle()
                    }) {
                        Image(systemName: "house")
                        Text(users[selectedUserIndex].name)
                    }
                    .popover(isPresented: $showPopup) {
                        List {
                            ForEach(users, id: \.id) { user in
                                Button(action: {
                                    self.selectedUserIndex = users.firstIndex(where: {$0 === user}) ?? 0
                                    self.showPopup.toggle()
                                }, label: {
                                    Label(user.name, systemImage: "house")
                                })
                                .buttonStyle(PlainButtonStyle())
                            }
                            .onMove(perform: { indices, newOffset in
                                move(from: indices, to: newOffset)
                            })
                        }
                    }
                    .padding()
                    .frame(maxWidth: .infinity)
                    
                    Image(systemName: "clock")
                }
                Divider()
            }
            Text("Detail View")
        }
    }
    
    func move(from source: IndexSet, to destination: Int) {
        let selected_user = users[selectedUserIndex]
        users.move(fromOffsets: source, toOffset: destination)
        selectedUserIndex = users.firstIndex(of: selected_user)!
    }
}

class User: Identifiable, Equatable {
    var id = UUID()
    var name: String = ""
    
    init(name: String) {
        self.name = name
    }
    
    static func == (lhs: User, rhs: User) -> Bool {
        return lhs.id == rhs.id
    }
}