Minor script improvements.

src/Squidex.Domain.Apps.Core.Operations/Scripting/ContentWrapper/ContentDataObject.cs

@@ -102,7 +102,7 @@ namespace Squidex.Domain.Apps.Core.Scripting.ContentWrapper
         {
             EnsurePropertiesInitialized();
 
-            return fieldProperties.GetOrDefault(propertyName) ?? new PropertyDescriptor(new ObjectInstance(Engine) { Extensible = true }, true, false, true);
+            return fieldProperties.GetOrAdd(propertyName, x => new ContentDataProperty(this, new ContentFieldObject(this, new ContentFieldData(), false)));
         }
 
         public override IEnumerable<KeyValuePair<string, PropertyDescriptor>> GetOwnProperties()

src/Squidex.Domain.Apps.Core.Operations/Scripting/ContentWrapper/ContentDataProperty.cs

@@ -30,7 +30,7 @@ namespace Squidex.Domain.Apps.Core.Scripting.ContentWrapper
                 {
                     if (value == null || !value.IsObject())
                     {
-                        throw new JavaScriptException("Can only assign object to content data.");
+                        throw new JavaScriptException("You can only assign objects to content data.");
                     }
 
                     var obj = value.AsObject();

tests/Squidex.Domain.Apps.Core.Tests/Operations/Scripting/ContentDataObjectTests.cs

@@ -32,6 +32,22 @@ namespace Squidex.Domain.Apps.Core.Operations.Scripting
             Assert.Equal(expected, result);
         }
 
+        [Fact]
+        public void Should_update_data_when_setting_lazy_field()
+        {
+            var original = new NamedContentData();
+
+            var expected =
+                new NamedContentData()
+                    .AddField("number",
+                        new ContentFieldData()
+                            .AddValue("iv", 1.0));
+
+            var result = ExecuteScript(original, @"data.number.iv = 1");
+
+            Assert.Equal(expected, result);
+        }
+
         [Fact]
         public void Should_update_data_defining_property_for_content()
         {