diff --git a/ICSharpCode.NRefactory/CSharp/Resolver/FindReferences.cs b/ICSharpCode.NRefactory/CSharp/Resolver/FindReferences.cs
index 5b7b3242d7..302bb853fe 100644
--- a/ICSharpCode.NRefactory/CSharp/Resolver/FindReferences.cs
+++ b/ICSharpCode.NRefactory/CSharp/Resolver/FindReferences.cs
@@ -31,21 +31,17 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 	/// </summary>
 	public class FindReferences
 	{
-		CancellationToken cancellationToken;
-		
 		/// <summary>
 		/// Callback that is invoked whenever a reference is found.
 		/// </summary>
 		public event Action<AstNode, ResolveResult> ReferenceFound;
 		
-		#region Constructor
-		public FindReferences(CancellationToken cancellationToken = default(CancellationToken))
-		{
-			this.cancellationToken = cancellationToken;
-		}
-		#endregion
-		
 		#region Properties
+		/// <summary>
+		/// Gets/Sets the cancellation token.
+		/// </summary>
+		public CancellationToken CancellationToken { get; set; }
+		
 		/// <summary>
 		/// Gets/Sets whether to find type references even if an alias is being used.
 		/// </summary>
@@ -224,7 +220,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		/// <summary>
 		/// Gets the file names that possibly contain references to the element being searched for.
 		/// </summary>
-		public IEnumerable<string> GetInterestingFileNames(SearchScope searchScope, ITypeResolveContext context)
+		public IList<string> GetInterestingFileNames(SearchScope searchScope, IEnumerable<ITypeDefinition> allTypes, ITypeResolveContext context)
 		{
 			IEnumerable<ITypeDefinition> interestingTypes;
 			if (searchScope.TopLevelTypeDefinition != null) {
@@ -234,41 +230,41 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 						interestingTypes = new [] { searchScope.TopLevelTypeDefinition.GetDefinition() };
 						break;
 					case Accessibility.Protected:
-						interestingTypes = GetInterestingTypesProtected(context, searchScope.TopLevelTypeDefinition);
+						interestingTypes = GetInterestingTypesProtected(allTypes, context, searchScope.TopLevelTypeDefinition);
 						break;
 					case Accessibility.Internal:
-						interestingTypes = GetInterestingTypesInternal(context, searchScope.TopLevelTypeDefinition.ProjectContent);
+						interestingTypes = GetInterestingTypesInternal(allTypes, context, searchScope.TopLevelTypeDefinition.ProjectContent);
 						break;
 					case Accessibility.ProtectedAndInternal:
-						interestingTypes = GetInterestingTypesProtected(context, searchScope.TopLevelTypeDefinition)
-							.Intersect(GetInterestingTypesInternal(context, searchScope.TopLevelTypeDefinition.ProjectContent));
+						interestingTypes = GetInterestingTypesProtected(allTypes, context, searchScope.TopLevelTypeDefinition)
+							.Intersect(GetInterestingTypesInternal(allTypes, context, searchScope.TopLevelTypeDefinition.ProjectContent));
 						break;
 					case Accessibility.ProtectedOrInternal:
-						interestingTypes = GetInterestingTypesProtected(context, searchScope.TopLevelTypeDefinition)
-							.Union(GetInterestingTypesInternal(context, searchScope.TopLevelTypeDefinition.ProjectContent));
+						interestingTypes = GetInterestingTypesProtected(allTypes, context, searchScope.TopLevelTypeDefinition)
+							.Union(GetInterestingTypesInternal(allTypes, context, searchScope.TopLevelTypeDefinition.ProjectContent));
 						break;
 					default:
-						interestingTypes = context.GetTypes();
+						interestingTypes = allTypes;
 						break;
 				}
 			} else {
-				interestingTypes = context.GetTypes();
+				interestingTypes = allTypes;
 			}
 			return (from typeDef in interestingTypes
 			        from part in typeDef.GetParts()
 			        where part.ParsedFile != null
 			        select part.ParsedFile.FileName
-			       ).Distinct(Platform.FileNameComparer);
+			       ).Distinct(Platform.FileNameComparer).ToList();
 		}
 		
-		IEnumerable<ITypeDefinition> GetInterestingTypesProtected(ITypeResolveContext context, ITypeDefinition referencedTypeDefinition)
+		IEnumerable<ITypeDefinition> GetInterestingTypesProtected(IEnumerable<ITypeDefinition> allTypes, ITypeResolveContext context, ITypeDefinition referencedTypeDefinition)
 		{
-			return referencedTypeDefinition.GetSubTypeDefinitions(context);
+			return allTypes.Where(t => t.IsDerivedFrom(referencedTypeDefinition, context));
 		}
 		
-		IEnumerable<ITypeDefinition> GetInterestingTypesInternal(ITypeResolveContext context, IProjectContent referencedProjectContent)
+		IEnumerable<ITypeDefinition> GetInterestingTypesInternal(IEnumerable<ITypeDefinition> allTypes, ITypeResolveContext context, IProjectContent referencedProjectContent)
 		{
-			return context.GetTypes().Where(t => referencedProjectContent.InternalsVisibleTo(t.ProjectContent, context));
+			return allTypes.Where(t => referencedProjectContent.InternalsVisibleTo(t.ProjectContent, context));
 		}
 		#endregion
 		
@@ -304,7 +300,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				throw new ArgumentNullException("compilationUnit");
 			if (context == null)
 				throw new ArgumentNullException("context");
-			cancellationToken.ThrowIfCancellationRequested();
+			this.CancellationToken.ThrowIfCancellationRequested();
 			if (searchScopes.Count == 0)
 				return;
 			foreach (SearchScope scope in searchScopes) {
@@ -318,7 +314,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 				else
 					navigator = new CompositeResolveVisitorNavigator(searchScopes.ToArray());
 				navigator = new DetectSkippableNodesNavigator(navigator, compilationUnit);
-				CSharpResolver resolver = new CSharpResolver(ctx, cancellationToken);
+				CSharpResolver resolver = new CSharpResolver(ctx, this.CancellationToken);
 				ResolveVisitor v = new ResolveVisitor(resolver, parsedFile, navigator);
 				v.Scan(compilationUnit);
 			}
diff --git a/ICSharpCode.NRefactory/CSharp/Resolver/LocalResolveResult.cs b/ICSharpCode.NRefactory/CSharp/Resolver/LocalResolveResult.cs
index ef056230f9..57779ab2a6 100644
--- a/ICSharpCode.NRefactory/CSharp/Resolver/LocalResolveResult.cs
+++ b/ICSharpCode.NRefactory/CSharp/Resolver/LocalResolveResult.cs
@@ -68,5 +68,10 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		{
 			return string.Format("[LocalResolveResult {0}]", variable);
 		}
+		
+		public override DomRegion GetDefinitionRegion()
+		{
+			return variable.Region;
+		}
 	}
 }
diff --git a/ICSharpCode.NRefactory/CSharp/Resolver/MemberResolveResult.cs b/ICSharpCode.NRefactory/CSharp/Resolver/MemberResolveResult.cs
index baaf504d7d..b47b4764c0 100644
--- a/ICSharpCode.NRefactory/CSharp/Resolver/MemberResolveResult.cs
+++ b/ICSharpCode.NRefactory/CSharp/Resolver/MemberResolveResult.cs
@@ -92,5 +92,10 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		{
 			return string.Format("[{0} {1}]", GetType().Name, member);
 		}
+		
+		public override DomRegion GetDefinitionRegion()
+		{
+			return member.Region;
+		}
 	}
 }
diff --git a/ICSharpCode.NRefactory/CSharp/Resolver/ResolveAtLocation.cs b/ICSharpCode.NRefactory/CSharp/Resolver/ResolveAtLocation.cs
index dcf78a2080..2f16a7ebf0 100644
--- a/ICSharpCode.NRefactory/CSharp/Resolver/ResolveAtLocation.cs
+++ b/ICSharpCode.NRefactory/CSharp/Resolver/ResolveAtLocation.cs
@@ -32,6 +32,8 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		                                    CancellationToken cancellationToken = default(CancellationToken))
 		{
 			AstNode node = cu.GetNodeAt(location);
+			if (node == null)
+				return null;
 			AstNode resolvableNode;
 			if (node is Identifier) {
 				resolvableNode = node.Parent;
diff --git a/ICSharpCode.NRefactory/CSharp/Resolver/ResolveResult.cs b/ICSharpCode.NRefactory/CSharp/Resolver/ResolveResult.cs
index 9f31e05720..40a9931e69 100644
--- a/ICSharpCode.NRefactory/CSharp/Resolver/ResolveResult.cs
+++ b/ICSharpCode.NRefactory/CSharp/Resolver/ResolveResult.cs
@@ -63,5 +63,10 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		{
 			return Enumerable.Empty<ResolveResult>();
 		}
+		
+		public virtual DomRegion GetDefinitionRegion()
+		{
+			return DomRegion.Empty;
+		}
 	}
 }
diff --git a/ICSharpCode.NRefactory/CSharp/Resolver/TypeResolveResult.cs b/ICSharpCode.NRefactory/CSharp/Resolver/TypeResolveResult.cs
index 1336357ba6..79815d6565 100644
--- a/ICSharpCode.NRefactory/CSharp/Resolver/TypeResolveResult.cs
+++ b/ICSharpCode.NRefactory/CSharp/Resolver/TypeResolveResult.cs
@@ -30,5 +30,14 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			: base(type)
 		{
 		}
+		
+		public override DomRegion GetDefinitionRegion()
+		{
+			ITypeDefinition def = this.Type.GetDefinition();
+			if (def != null)
+				return def.Region;
+			else
+				return DomRegion.Empty;
+		}
 	}
 }