Fixing an issue with thread creation and selected items notifications.

Wino.Core.Domain/Models/MailItem/IMailHashContainer.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+
+namespace Wino.Core.Domain.Models.MailItem
+{
+    /// <summary>
+    /// An interface that returns the UniqueId store for IMailItem.
+    /// For threads, it may be multiple items.
+    /// For single mails, it'll always be one item.
+    /// </summary>
+    public interface IMailHashContainer
+    {
+        IEnumerable<Guid> GetContainingIds();
+    }
+}

Wino.Core.Domain/Models/MailItem/IMailItem.cs

@@ -6,7 +6,7 @@ namespace Wino.Core.Domain.Models.MailItem
     /// <summary>
     /// Interface of simplest representation of a MailCopy.
     /// </summary>
-    public interface IMailItem
+    public interface IMailItem : IMailHashContainer
     {
         Guid UniqueId { get; }
         string Id { get; }

Wino.Core.Domain/Models/MailItem/ThreadMailItem.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
 using Wino.Core.Domain.Entities;
@@ -40,6 +41,8 @@ namespace Wino.Core.Domain.Models.MailItem
             }
         }
 
+        public IEnumerable<Guid> GetContainingIds() => ThreadItems?.Select(a => a.UniqueId) ?? default;
+
         #region IMailItem
 
         public Guid UniqueId => LatestMailItem?.UniqueId ?? Guid.Empty;