diff --git a/src/Main/Base/Project/Dom/IModelCollection.cs b/src/Main/Base/Project/Dom/IModelCollection.cs
index 69f92760f6..7c6f5ece7a 100644
--- a/src/Main/Base/Project/Dom/IModelCollection.cs
+++ b/src/Main/Base/Project/Dom/IModelCollection.cs
@@ -7,44 +7,6 @@ using System.Linq;
 
 namespace ICSharpCode.SharpDevelop.Dom
 {
-	/// <summary>
-	/// Event handler for the <see cref="IModelCollection{T}.CollectionChanged"/> event.
-	/// </summary>
-	/// <remarks>
-	/// We don't use the classic 'EventArgs' model for this event, because a EventArgs-class couldn't be covariant.
-	/// </remarks>
-	public delegate void ModelCollectionChangedEventHandler<in T>(IReadOnlyCollection<T> removedItems, IReadOnlyCollection<T> addedItems);
-	
-	public class ModelCollectionChangedEvent<T>
-	{
-		List<ModelCollectionChangedEventHandler<T>> _handlers = new List<ModelCollectionChangedEventHandler<T>>();
-		
-		public void AddHandler(ModelCollectionChangedEventHandler<T> handler)
-		{
-			if (handler != null)
-				_handlers.Add(handler);
-		}
-		
-		public void RemoveHandler(ModelCollectionChangedEventHandler<T> handler)
-		{
-			_handlers.Remove(handler);
-		}
-		
-		public void Fire(IReadOnlyCollection<T> removedItems, IReadOnlyCollection<T> addedItems)
-		{
-			foreach (var handler in _handlers.ToArray()) {
-				handler(removedItems, addedItems);
-			}
-		}
-		
-		public bool ContainsHandlers
-		{
-			get {
-				return _handlers.Count > 0;
-			}
-		}
-	}
-	
 	/// <summary>
 	/// A read-only collection that provides change notifications.
 	/// </summary>
diff --git a/src/Main/Base/Project/Dom/ModelCollectionChangedEvent.cs b/src/Main/Base/Project/Dom/ModelCollectionChangedEvent.cs
new file mode 100644
index 0000000000..686330d4e3
--- /dev/null
+++ b/src/Main/Base/Project/Dom/ModelCollectionChangedEvent.cs
@@ -0,0 +1,52 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+namespace ICSharpCode.SharpDevelop.Dom
+{
+	/// <summary>
+	/// Event handler for the <see cref="IModelCollection{T}.CollectionChanged"/> event.
+	/// </summary>
+	/// <remarks>
+	/// We don't use the classic 'EventArgs' model for this event, because a EventArgs-class couldn't be covariant.
+	/// </remarks>
+	public delegate void ModelCollectionChangedEventHandler<in T>(IReadOnlyCollection<T> removedItems, IReadOnlyCollection<T> addedItems);
+
+	/// <summary>
+	/// Helper class for <see cref="IModelCollection.CollectionChanged"/> implementations.
+	/// This is necessary because <c>Delegate.Combine</c> does not work with
+	/// co-/contravariant delegates.
+	/// </summary>
+	public class ModelCollectionChangedEvent<T>
+	{
+		List<ModelCollectionChangedEventHandler<T>> _handlers = new List<ModelCollectionChangedEventHandler<T>>();
+		
+		public void AddHandler(ModelCollectionChangedEventHandler<T> handler)
+		{
+			if (handler != null)
+				_handlers.Add(handler);
+		}
+		
+		public void RemoveHandler(ModelCollectionChangedEventHandler<T> handler)
+		{
+			_handlers.Remove(handler);
+		}
+		
+		public void Fire(IReadOnlyCollection<T> removedItems, IReadOnlyCollection<T> addedItems)
+		{
+			foreach (var handler in _handlers.ToArray()) {
+				handler(removedItems, addedItems);
+			}
+		}
+		
+		public bool ContainsHandlers {
+			get {
+				return _handlers.Count > 0;
+			}
+		}
+	}
+}
+
+
diff --git a/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj b/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
index 7ffe4a75db..8578f89080 100644
--- a/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
+++ b/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
@@ -111,6 +111,7 @@
     <Compile Include="Dom\IModelCollection.cs" />
     <Compile Include="Dom\ITreeNodeFactory.cs" />
     <Compile Include="Dom\KeyedModelCollection.cs" />
+    <Compile Include="Dom\ModelCollectionChangedEvent.cs" />
     <Compile Include="Dom\ModelCollectionLinq.cs" />
     <Compile Include="Dom\ImmutableModelCollection.cs" />
     <Compile Include="Dom\ModelCollectionTreeNode.cs" />