could not make NavigationView fully extend Y-direction. Tried .edgesIgnoringSafeArea(.all) and all options of .frame(). Preview Provider shows that everything's cool, but Simulator and a real device show the opposite. (Pics attached)
The code:
import SwiftUI
struct ContentView: View {
        var body: some View {
        NavigationView{
            ZStack{
                Color.blue
                VStack{
                    Text("Hello, World!")
                        .foregroundColor(Color.blue)
                        .fontWeight(.bold)
                        .font(.system(size: 36))
                }
            }
            .navigationBarHidden(true)
            .navigationBarTitle("")
            .navigationBarBackButtonHidden(true)
            .frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: .infinity, alignment: .center)
            .edgesIgnoringSafeArea(.all)
        }
    }
}
