diff --git a/src/Squidex.Domain.Apps.Core.Model/Schemas/Field{T}.cs b/src/Squidex.Domain.Apps.Core.Model/Schemas/Field{T}.cs
index b32425c4d..e1da04c62 100644
--- a/src/Squidex.Domain.Apps.Core.Model/Schemas/Field{T}.cs
+++ b/src/Squidex.Domain.Apps.Core.Model/Schemas/Field{T}.cs
@@ -11,7 +11,7 @@ using Squidex.Infrastructure;
 
 namespace Squidex.Domain.Apps.Core.Schemas
 {
-    public sealed class Field<T> : Field where T : FieldProperties, new()
+    public sealed class Field<T> : Field, IField<T> where T : FieldProperties, new()
     {
         private T properties;