ios – SwiftUI NavigationStack ToolbarItem exhibits undesirable round background behind icon

I’m attempting to create a easy toolbar button in SwiftUI utilizing NavigationStack, nevertheless it at all times exhibits an undesirable mild round/rounded background across the icon.

I wish to take away the round background from the icon.
Right here is my present code:

    var physique: some View {
        NavigationStack {
            ZStack {
                Shade.indigo.ignoresSafeArea()
            }
            .navigationTitle(Strings.chats)
            .navigationBarTitleDisplayMode(.massive)
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button {
                    } label: {
                        Picture(systemName: "plus")
                    }
                }
            }
        }
        .toolbarBackground(.clear, for: .navigationBar)
        .toolbarBackgroundVisibility(.hidden, for: .navigationBar)
        
    }