diff --git a/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj b/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
index f9b57fad1c..660b699fe3 100644
--- a/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
+++ b/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
@@ -702,6 +702,8 @@
     <Compile Include="Src\Services\RefactoringService\FindReferencesAndRenameHelper.cs" />
     <Compile Include="Src\Internal\Doozers\DirectoryDoozer.cs" />
     <Compile Include="Src\Gui\Components\StringListEditor.cs" />
+    <Compile Include="Src\Dom\Implementations\NullReturnType.cs" />
+    <Compile Include="Src\Dom\Implementations\AnonymousMethodReturnType.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\Libraries\DockPanel_Src\WinFormsUI\WinFormsUI.csproj">
diff --git a/src/Main/Base/Project/Src/Dom/Implementations/AnonymousMethodReturnType.cs b/src/Main/Base/Project/Src/Dom/Implementations/AnonymousMethodReturnType.cs
new file mode 100644
index 0000000000..62ecb43bf2
--- /dev/null
+++ b/src/Main/Base/Project/Src/Dom/Implementations/AnonymousMethodReturnType.cs
@@ -0,0 +1,55 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt">2002-2005 AlphaSierraPapa</copyright>
+//     <license see="prj:///doc/license.txt">GNU General Public License</license>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Collections.Generic;
+using ICSharpCode.Core;
+
+namespace ICSharpCode.SharpDevelop.Dom
+{
+	/// <summary>
+	/// The return type of anonymous method expressions or lambda expressions.
+	/// </summary>
+	public sealed class AnonymousMethodReturnType : ProxyReturnType
+	{
+		public override bool IsDefaultReturnType {
+			get {
+				return false;
+			}
+		}
+		
+		public override IReturnType BaseType {
+			get {
+				return ReflectionReturnType.Delegate;
+			}
+		}
+		
+		public override string Name {
+			get {
+				return "delegate";
+			}
+		}
+		
+		public override string FullyQualifiedName {
+			get {
+				return Name;
+			}
+		}
+		
+		public override string Namespace {
+			get {
+				return "";
+			}
+		}
+		
+		public override string DotNetName {
+			get {
+				return Name;
+			}
+		}
+	}
+}
diff --git a/src/Main/Base/Project/Src/Dom/Implementations/NullReturnType.cs b/src/Main/Base/Project/Src/Dom/Implementations/NullReturnType.cs
new file mode 100644
index 0000000000..35903dbd77
--- /dev/null
+++ b/src/Main/Base/Project/Src/Dom/Implementations/NullReturnType.cs
@@ -0,0 +1,42 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt">2002-2005 AlphaSierraPapa</copyright>
+//     <license see="prj:///doc/license.txt">GNU General Public License</license>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Collections.Generic;
+using ICSharpCode.Core;
+
+namespace ICSharpCode.SharpDevelop.Dom
+{
+	/// <summary>The type of the 'null'/'nothing' literal.</summary>
+	[Serializable]
+	public sealed class NullReturnType : AbstractReturnType
+	{
+		public static readonly NullReturnType Instance = new NullReturnType();
+		
+		public override bool Equals(object o)
+		{
+			return o is NullReturnType;
+		}
+		
+		public override int GetHashCode()
+		{
+			return 0;
+		}
+		
+		public override bool IsDefaultReturnType {
+			get {
+				return false;
+			}
+		}
+		
+		public override IClass GetUnderlyingClass()     { return null; }
+		public override List<IMethod>   GetMethods()    { return new List<IMethod>(); }
+		public override List<IProperty> GetProperties() { return new List<IProperty>(); }
+		public override List<IField>    GetFields()     { return new List<IField>(); }
+		public override List<IEvent>    GetEvents()     { return new List<IEvent>(); }
+	}
+}
diff --git a/src/Main/Base/Project/Src/Dom/NRefactoryResolver/TypeVisitor.cs b/src/Main/Base/Project/Src/Dom/NRefactoryResolver/TypeVisitor.cs
index d3d00c9723..2f2775e16a 100644
--- a/src/Main/Base/Project/Src/Dom/NRefactoryResolver/TypeVisitor.cs
+++ b/src/Main/Base/Project/Src/Dom/NRefactoryResolver/TypeVisitor.cs
@@ -30,10 +30,11 @@ namespace ICSharpCode.SharpDevelop.Dom.NRefactoryResolver
 		
 		public override object Visit(PrimitiveExpression primitiveExpression, object data)
 		{
-			if (primitiveExpression.Value != null) {
+			if (primitiveExpression.Value == null) {
+				return NullReturnType.Instance;
+			} else {
 				return ReflectionReturnType.CreatePrimitive(primitiveExpression.Value.GetType());
 			}
-			return null;
 		}
 		
 		public override object Visit(BinaryOperatorExpression binaryOperatorExpression, object data)
@@ -444,7 +445,7 @@ namespace ICSharpCode.SharpDevelop.Dom.NRefactoryResolver
 		
 		public override object Visit(AnonymousMethodExpression anonymousMethodExpression, object data)
 		{
-			return ReflectionReturnType.Delegate;
+			return new AnonymousMethodReturnType();
 		}
 		
 		public override object Visit(ArrayInitializerExpression arrayInitializerExpression, object data)
diff --git a/src/Main/Base/Project/Src/Services/Debugger/DefaultDebugger.cs b/src/Main/Base/Project/Src/Services/Debugger/DefaultDebugger.cs
index f10aeeafca..d485138567 100644
--- a/src/Main/Base/Project/Src/Services/Debugger/DefaultDebugger.cs
+++ b/src/Main/Base/Project/Src/Services/Debugger/DefaultDebugger.cs
@@ -57,8 +57,8 @@ namespace ICSharpCode.Core
 		{
 			attachedProcess.Exited -= new EventHandler(AttachedProcessExited);
 			attachedProcess.Dispose();
-			attachedProcess = null;	
-			OnDebugStopped(EventArgs.Empty);
+			attachedProcess = null;
+			WorkbenchSingleton.SafeThreadAsyncCall(this, "OnDebugStopped", EventArgs.Empty);
 		}
 
 		public void StartWithoutDebugging(ProcessStartInfo processStartInfo)