SwiftUI 2 - How to prevent the top section from closing in a list in macOS and iPadOS

Question

In a SwiftUI 2 navigation bar I have a list with multiple sections. All sections have a header, however I want the top section to never be closed and the elements will never be hidden. This is ask for only the first header and also want that the disclosure indicator / collapsing symbol to be gone or hidden.

Can this be done in SwiftUI 2? I want to have this to work in macOS and iPadOS.

@State var agendaViews: [String] = ["Agenda", "Client", "Next Client"]
@State var treatmentViews: [String] = ["Treatment", "Products", "Merchandising"]
@State var selectionAgenda: String?

var body: some View {
    NavigationView {
        VStack {
            List(selection: $selectionAgenda) {
                Section(header: ListHeader()) {    // <<<<<<< For this section no Close Icon and No way to close this section.
                    ForEach(agendaViews, id: \.self) { string in
                        NavigationLink(destination: DetailsView(test: string)) {
                            Text(string)
                        }
                    }
                }
                Section(header: ListHeader2(), footer: ListFooter2()) {
                    ForEach(treatmentViews, id: \.self) { string in
                        NavigationLink(destination: DetailsView2(test: string)) {
                            Text(string)
                        }
                    }
                }
            }.listStyle(SidebarListStyle())
    }
  }
}

struct ListHeader1: View {
  var body: some View {
      HStack {
        Image(systemName: "calendar")
        Text("Agenda")
      }
    }
  }
  struct ListHeader2: View {
  var body: some View {
     HStack {
        Image(systemName: "person.3")
        Text("Clienten")
     }
    }
   }

   struct ListFooter3: View {
     var body: some View {
       Text("===")
     }
   }

I hope my question is clear. As always thank you very much.

Some image added to show that a section header has a close and open button.

Answer 1

Use the collapsible view modifier for the Section. Your first section would become:

Section(header: ListHeader()) {
    ForEach(agendaViews, id: \.self) { string in
        NavigationLink(destination: DetailsView(test: string)) {
            Text(string)
        }
    }
}
.collapsible(false)

Answer 2

Not really 'the' answer but for now a solution to my issue. Still if someone knows a better solution please correct me.

I did change the following in the code:

var body: some View {
        VStack  {
            List(selection: $selectionAgenda) {
                ListHeader1()
                ForEach(agendaViews, id: \.self) { string in
                    NavigationLink(destination: DetailsView2(test: string)) {
                        Text(string)
                    }
                }
                Section(header: ListHeader2(), footer: ListFooter2()) {
                    ForEach(treatmentViews, id: \.self) { string in
                        NavigationLink(destination: DetailsView2(test: string)) {
                            Text(string)
                        }

                    }

                }
            }
            .listStyle(SidebarListStyle())
       }
   }


struct ListHeader1: View {
    var body: some View {
        HStack {
            Image(systemName: "calendar")
            Text("Agenda")
        }.font(.title2)
    }
}

struct ListHeader2: View {
    var body: some View {
        HStack {
            Image(systemName: "person.3")
            Text("Clienten")
        }.font(.title2)
    }
}

In text, I did remove only the first section of the list and replace it with just the Header View, and Voila, on the iPad it looks good for the moment.