Fixes issue of observable collections, event binding and deep cloning

src/Umbraco.Core/Models/Content.cs

@@ -438,6 +438,7 @@ namespace Umbraco.Core.Models
             _contentType = contentType;
             ContentTypeBase = contentType;
             Properties.EnsurePropertyTypes(PropertyTypes);
+            //TODO: Shouldn't we remove this event handler first before re-adding it in case the handler already exists
             Properties.CollectionChanged += PropertiesChanged;
         }
 
@@ -455,6 +456,7 @@ namespace Umbraco.Core.Models
                 _contentType = contentType;
                 ContentTypeBase = contentType;
                 Properties.EnsureCleanPropertyTypes(PropertyTypes);
+                //TODO: Shouldn't we remove this event handler first before re-adding it in case the handler already exists
                 Properties.CollectionChanged += PropertiesChanged;
                 return;
             }
@@ -500,10 +502,18 @@ namespace Umbraco.Core.Models
         public override object DeepClone()
         {
             var clone = (Content) base.DeepClone();
+
             //turn off change tracking
             clone.DisableChangeTracking();
-            //need to manually clone this since it's not settable
-            clone._contentType = (IContentType)ContentType.DeepClone();
+
+            //if culture infos exist then deal with event bindings
+            if (clone._publishInfos != null)
+            {
+                clone._publishInfos.CollectionChanged -= this.PublishNamesCollectionChanged;    //clear this event handler if any
+                clone._publishInfos = (CultureNameCollection)_publishInfos.DeepClone();         //manually deep clone
+                clone._publishInfos.CollectionChanged += clone.PublishNamesCollectionChanged;   //re-assign correct event handler
+            }
+
             //this shouldn't really be needed since we're not tracking
             clone.ResetDirtyProperties(false);
             //re-enable tracking

src/Umbraco.Core/Models/ContentBase.cs

@@ -113,7 +113,11 @@ namespace Umbraco.Core.Models
         /// <summary>
         /// Gets or sets the collection of properties for the entity.
         /// </summary>
+        /// <remarks>
+        /// Marked DoNotClone since we'll manually clone the underlying field to deal with the event handling
+        /// </remarks>
         [DataMember]
+        [DoNotClone]
         public virtual PropertyCollection Properties
         {
             get => _properties;
@@ -477,5 +481,39 @@ namespace Umbraco.Core.Models
         }
 
         #endregion
+
+        /// <summary>
+        /// Override to deal with specific object instances
+        /// </summary>
+        /// <returns></returns>
+        public override object DeepClone()
+        {
+            var clone = (ContentBase)base.DeepClone();
+            //turn off change tracking
+            clone.DisableChangeTracking();
+
+            //if culture infos exist then deal with event bindings
+            if (clone._cultureInfos != null)
+            {
+                clone._cultureInfos.CollectionChanged -= this.CultureNamesCollectionChanged;    //clear this event handler if any
+                clone._cultureInfos = (CultureNameCollection)_cultureInfos.DeepClone();         //manually deep clone
+                clone._cultureInfos.CollectionChanged += clone.CultureNamesCollectionChanged;   //re-assign correct event handler
+            }
+
+            //if properties exist then deal with event bindings
+            if (clone._properties != null)
+            {
+                clone._properties.CollectionChanged -= this.PropertiesChanged;    //clear this event handler if any
+                clone._properties = (PropertyCollection)_properties.DeepClone();  //manually deep clone
+                clone._properties.CollectionChanged += clone.PropertiesChanged;   //re-assign correct event handler
+            }
+
+            //this shouldn't really be needed since we're not tracking
+            clone.ResetDirtyProperties(false);
+            //re-enable tracking
+            clone.EnableChangeTracking();
+
+            return clone;
+        }
     }
 }

src/Umbraco.Core/Models/Entities/EntityBase.cs

@@ -13,6 +13,10 @@ namespace Umbraco.Core.Models.Entities
     [DebuggerDisplay("Id: {" + nameof(Id) + "}")]
     public abstract class EntityBase : BeingDirtyBase, IEntity
     {
+#if DEBUG
+        public Guid InstanceId = Guid.NewGuid();
+#endif
+
         private static readonly Lazy<PropertySelectors> Ps = new Lazy<PropertySelectors>();
 
         private bool _hasIdentity;
@@ -161,6 +165,11 @@ namespace Umbraco.Core.Models.Entities
             var unused = Key; // ensure that 'this' has a key, before cloning
             var clone = (EntityBase) MemberwiseClone();
 
+#if DEBUG
+            clone.InstanceId = Guid.NewGuid();
+#endif
+
+
             // clear changes (ensures the clone has its own dictionaries)
             // then disable change tracking
             clone.ResetDirtyProperties(false);