The Dimensions view takes any combination of views and shows the width & height of all the views combined using PreferenceKeys. As seen in Example 1: When constructing all the views inside Dimensions, it will work and show the sizes. While in Examples 2 & 3: If the views are constructed outside of Dimensions, it will not work. QUESTION: How would it work when the views are constructed outside? Thanks. Running on Xcode Version 12.5.1 (12E507) target iOS 14.5 The code: import SwiftUI struct ContentView: View {          var body: some View {         VStack {                          // Example 1             Dimensions {                 HStack {                                          Text("Hello, world!")                         .padding()                                          // HelloWorldVariable   // <===== THIS WILL BREAK IT                     // HelloWorldView()     // <===== THIS WILL BREAK IT                 }             }.background(Color.blue)                          // Example 2             Dimensions {                 HStack {                     HelloWorldVariable // <===== THIS DOES NOT WORK in the HStack                 }             }.background(Color.green)                          // Example 3             Dimensions {                 HStack {                     HelloWorldView() // <===== THIS DOES NOT WORK in the HStack                 }             }.background(Color.yellow)         }     }          private var HelloWorldVariable: some View {         Text("Hello, world!")             .padding()     } } // MARK:- HelloWorldView struct HelloWorldView: View {     var body: some View {         Text("Hello, world!")             .padding()     } } // MARK:- Dimensions struct Dimensions<Content: View>: View {          private var content: () -> Content     @State private var contentSize: CGSize = .zero          init(@ViewBuilder content: @escaping () -> Content) {         self.content = content     }          var body: some View {         VStack {             content()                 .background(ObserveViewDimensions())                          VStack {                 Text("contentWidth \(contentSize.width)")                 Text("contentHeight \(contentSize.height)")             }         }         .onPreferenceChange(DimensionsKey.self, perform: { value in             self.contentSize = value         })     } } // MARK:- ObserveViewDimensions struct ObserveViewDimensions: View {     var body: some View {         GeometryReader { geometry in             Color.clear.preference(key: DimensionsKey.self, value: geometry.size)         }     } } // MARK:- DimensionsKey struct DimensionsKey: PreferenceKey {     static var defaultValue: CGSize = .zero          static func reduce(value: inout CGSize, nextValue: () -> CGSize) {         value = nextValue()     }          typealias Value = CGSize } // MARK:- Preview struct ContentView_Previews: PreviewProvider {     static var previews: some View {         ContentView()     } }