Fixed an issue with CoreRow empty values being DBNull, rather than NULL

(Re)fixed an issue when populating Entity User Properties
Fixed an Issue where Code Popup Editors would detect the wrong property to update

InABox.Core/CoreTable/CoreRow.cs

@@ -106,7 +106,7 @@ namespace InABox.Core
                         }
 
                         var setter = setters[i];
-                        if (setter != null && value != null)
+                        if (setter != null && value != null && !(value is System.DBNull))
                             setter.Invoke(obj, value);
                         else
                             CoreUtils.SetPropertyValue(obj, column, value);

InABox.Core/DatabaseSchema/CustomProperty.cs

@@ -118,6 +118,7 @@ namespace InABox.Core
                 {
                     type = typeof(object);
                 }
+                CheckExpressions();
 
                 IsEntityLink = type.GetInterfaces().Contains(typeof(IEntityLink));
                 IsEnclosedEntity = type.GetInterfaces().Contains(typeof(IEnclosedEntity));

InABox.Core/DatabaseSchema/DatabaseSchema.cs

@@ -334,7 +334,7 @@ namespace InABox.Core
         {
             entity.UserProperties.Load(Properties(entity.GetType())
                 .Where(x => x is CustomProperty)
-                .Select(x => new KeyValuePair<string, object?>(x.Name, x.PropertyType)));
+                .Select(x => new KeyValuePair<string, object?>(x.Name, DefaultValue(x.PropertyType))));
         }
     }
 }

inabox.wpf/DynamicGrid/Editors/CodePopupEditor/CodePopupEditorControl.cs

@@ -314,7 +314,7 @@ public class CodePopupEditorControl : DynamicEditorControl<Guid, CodePopupEditor
     private string GetCodeColumn(Type type)
     {
         var prop = DatabaseSchema.Properties(type)
-            .Where(x => x.Editor is BaseCodeEditor && !x.HasParentEntityLink())
+            .Where(x => x.Editor is UniqueCodeEditor && !x.HasParentEntityLink())
             .FirstOrDefault() ?? throw new Exception($"No code property for {type.EntityName()}");
         return prop.Name;
     }