diff --git a/Code/IHM/Navigator.cs b/Code/IHM/Navigator.cs
index 5509663..cff6558 100644
--- a/Code/IHM/Navigator.cs
+++ b/Code/IHM/Navigator.cs
@@ -59,7 +59,7 @@ namespace IHM
 
         private KeyValuePair<string, Func<UserControl>> selectedUserControlCreator;
 
-        public event PropertyChangedEventHandler PropertyChanged;
+        public event PropertyChangedEventHandler? PropertyChanged;
         void OnPropertyChanged([CallerMemberName] string propertyName = "")
             => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));