title: VStack's frame size doesn't fill all of the screen
body: <p>I was creating some View using SwiftUI and encountered a weird bug with VStack's frame dimensions. The gradient doesn't fill all of the screen's height. 
  Is that just Xcode bug or am I doing something wrong?
  <a href="https://i.stack.imgur.com/5rAuP.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/5rAuP.jpg" alt="enter image description here"></a></p>
  
  <pre><code>struct WelcomeView : View {
  
      private let colors = [
          Color(red: 29/255, green: 151/255, blue: 108/255),
          Color(red: 147/255, green: 249/255, blue: 185/255)
      ]
  
      let screenSize = UIScreen.main.bounds
  
      var body: some View {
          VStack {
              Text("Content here")
          }
          .frame(width: screenSize.width, height: screenSize.height)
          .background(LinearGradient(gradient: Gradient(colors: colors), 
     startPoint: .bottom, endPoint: .top), cornerRadius: 0)
  
      }
  }
  </code></pre>