Think I've managed to repro Core2D leak.

samples/BindingTest/TestItemView.paml

@@ -1,6 +1,6 @@
 <UserControl xmlns="https://github.com/perspex">
   <StackPanel>
     <TextBlock Classes="h1" Text="{Binding StringValue}"/>
-    <TextBlock Text="{Binding Detail}"/>
+    <TextBox Text="{Binding Detail}" AcceptsReturn="True"/>
   </StackPanel>
 </UserControl>

samples/BindingTest/ViewModels/MainWindowViewModel.cs

@@ -17,7 +17,7 @@ namespace BindingTest.ViewModels
                 Enumerable.Range(0, 20).Select(x => new TestItem
                 {
                     StringValue = "Item " + x,
-                    Detail = "Item " + " details",
+                    Detail = "Item " + x + " details",
                 }));
 
             SelectedItems = new ObservableCollection<TestItem>();

src/Perspex.Base/Collections/InccDebug.cs

@@ -0,0 +1,12 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System;
+
+namespace Perspex.Collections
+{
+    public interface InccDebug
+    {
+        Delegate[] GetCollectionChangedSubscribers();
+    }
+}

src/Perspex.Base/Collections/PerspexList.cs

@@ -53,7 +53,7 @@ namespace Perspex.Collections
     /// </item>
     /// </list>
     /// </remarks>
-    public class PerspexList<T> : IPerspexList<T>, IList
+    public class PerspexList<T> : IPerspexList<T>, IList, InccDebug
     {
         private List<T> _inner;
         private NotifyCollectionChangedEventHandler _collectionChanged;
@@ -434,6 +434,9 @@ namespace Perspex.Collections
             return _inner.GetEnumerator();
         }
 
+        /// <inheritdoc/>
+        Delegate[] InccDebug.GetCollectionChangedSubscribers() => _collectionChanged?.GetInvocationList();
+
         /// <summary>
         /// Raises the <see cref="CollectionChanged"/> event with an add action.
         /// </summary>

src/Perspex.Base/Perspex.Base.csproj

@@ -43,6 +43,7 @@
     <Compile Include="..\Shared\SharedAssemblyInfo.cs">
       <Link>Properties\SharedAssemblyInfo.cs</Link>
     </Compile>
+    <Compile Include="Collections\InccDebug.cs" />
     <Compile Include="Data\AssignBindingAttribute.cs" />
     <Compile Include="Data\BindingOperations.cs" />
     <Compile Include="Data\InstancedBinding.cs" />

src/Perspex.Controls/Control.cs

@@ -528,6 +528,11 @@ namespace Perspex.Controls
             {
                 child.OnDetachedFromLogicalTree(e);
             }
+
+            if (((InccDebug)_classes).GetCollectionChangedSubscribers()?.Length > 0)
+            {
+                System.Diagnostics.Debugger.Break();
+            }
         }
 
         /// <inheritdoc/>