diff --git a/CliFx.Demo/Domain/LibraryProvider.cs b/CliFx.Demo/Domain/LibraryProvider.cs
index 6e9e79b..4fe2137 100644
--- a/CliFx.Demo/Domain/LibraryProvider.cs
+++ b/CliFx.Demo/Domain/LibraryProvider.cs
@@ -21,7 +21,7 @@ namespace CliFx.Demo.Domain
 
             var data = File.ReadAllText(StorageFilePath);
 
-            return JsonConvert.DeserializeObject<Library>(data);
+            return JsonConvert.DeserializeObject<Library>(data) ?? Library.Empty;
         }
 
         public Book? TryGetBook(string title) => GetLibrary().Books.FirstOrDefault(b => b.Title == title);
diff --git a/CliFx.Tests/HelpTextSpecs.cs b/CliFx.Tests/HelpTextSpecs.cs
index cf9a646..325eb09 100644
--- a/CliFx.Tests/HelpTextSpecs.cs
+++ b/CliFx.Tests/HelpTextSpecs.cs
@@ -590,10 +590,10 @@ public enum CustomEnum { One, Two, Three }
 public class Command : ICommand
 {
     [CommandParameter(0)]
-    public List<CustomEnum> Foo { get; set; }
+    public IReadOnlyList<CustomEnum> Foo { get; set; }
 
     [CommandOption(""bar"")]
-    public List<CustomEnum> Bar { get; set; }
+    public IReadOnlyList<CustomEnum> Bar { get; set; }
 
     public ValueTask ExecuteAsync(IConsole console) => default;
 }
@@ -638,7 +638,7 @@ public class Command : ICommand
     public CustomEnum? Foo { get; set; }
 
     [CommandOption(""bar"")]
-    public List<CustomEnum?> Bar { get; set; }
+    public IReadOnlyList<CustomEnum?> Bar { get; set; }
 
     public ValueTask ExecuteAsync(IConsole console) => default;
 }
diff --git a/CliFx/Schema/BindablePropertyDescriptor.cs b/CliFx/Schema/BindablePropertyDescriptor.cs
index 6eacafa..e620ddb 100644
--- a/CliFx/Schema/BindablePropertyDescriptor.cs
+++ b/CliFx/Schema/BindablePropertyDescriptor.cs
@@ -21,8 +21,20 @@ namespace CliFx.Schema
 
         public IReadOnlyList<object?> GetValidValues()
         {
-            var underlyingType = Type.TryGetEnumerableUnderlyingType() ?? Type;
-            underlyingType = underlyingType.TryGetNullableUnderlyingType() ?? underlyingType;
+            static Type GetUnderlyingType(Type type)
+            {
+                var enumerableUnderlyingType = type.TryGetEnumerableUnderlyingType();
+                if (enumerableUnderlyingType is not null)
+                    return GetUnderlyingType(enumerableUnderlyingType);
+
+                var nullableUnderlyingType = type.TryGetNullableUnderlyingType();
+                if (nullableUnderlyingType is not null)
+                    return GetUnderlyingType(nullableUnderlyingType);
+
+                return type;
+            }
+            
+            var underlyingType = GetUnderlyingType(Type);
 
             // We can only get valid values for enums
             if (underlyingType.IsEnum)