diff --git a/AddIns/ICSharpCode.SharpDevelop.addin b/AddIns/ICSharpCode.SharpDevelop.addin
index f14ac5da2f..047acacf9a 100644
--- a/AddIns/ICSharpCode.SharpDevelop.addin
+++ b/AddIns/ICSharpCode.SharpDevelop.addin
@@ -2182,4 +2182,12 @@
 		          icon = "Icons.16x16.CopyIcon"
 		          class = "ICSharpCode.SharpDevelop.Commands.Copy"/>
 	</Path>
+	
+	<Path name="/SharpDevelop/Services/ParserService/SingleFileGacReferences">
+		<String id = "System" text = "System"/>
+		<String id = "System.Data" text = "System.Data"/>
+		<String id = "System.Drawing" text = "System.Drawing"/>
+		<String id = "System.Windows.Forms" text = "System.Windows.Forms"/>
+		<String id = "System.Xml" text = "System.Xml"/>
+	</Path>
 </AddIn>
diff --git a/src/AddIns/BackendBindings/VBNetBinding/Project/VBNetBinding.addin b/src/AddIns/BackendBindings/VBNetBinding/Project/VBNetBinding.addin
index 3339943c6a..b03238d4a6 100644
--- a/src/AddIns/BackendBindings/VBNetBinding/Project/VBNetBinding.addin
+++ b/src/AddIns/BackendBindings/VBNetBinding/Project/VBNetBinding.addin
@@ -112,4 +112,8 @@
 		                 projectfileextension = ".vbproj"
 		                 class                = "VBNetBinding.VBNetLanguageBinding" />
 	</Path>
+	
+	<Path name="/SharpDevelop/Services/ParserService/SingleFileGacReferences">
+		<String id = "Microsoft.VisualBasic" text = "Microsoft.VisualBasic"/>
+	</Path>
 </AddIn>
diff --git a/src/Libraries/NRefactory/Project/Src/Lexer/Special/PreProcessingDirective.cs b/src/Libraries/NRefactory/Project/Src/Lexer/Special/PreProcessingDirective.cs
index 5f54fa7dec..b540addff7 100644
--- a/src/Libraries/NRefactory/Project/Src/Lexer/Special/PreProcessingDirective.cs
+++ b/src/Libraries/NRefactory/Project/Src/Lexer/Special/PreProcessingDirective.cs
@@ -25,7 +25,7 @@ namespace ICSharpCode.NRefactory
 		{
 			string cmd = dir.Cmd;
 			string arg = dir.Arg;
-			if (cmd.Equals("#end", StringComparison.InvariantCultureIgnoreCase)) {
+			if (cmd.Equals("#End", StringComparison.InvariantCultureIgnoreCase)) {
 				if (arg.ToLowerInvariant().StartsWith("region")) {
 					cmd = "#endregion";
 					arg = "";
@@ -33,7 +33,9 @@ namespace ICSharpCode.NRefactory
 					cmd = "#endif";
 					arg = "";
 				}
-			} else if (cmd.Equals("#if", StringComparison.InvariantCultureIgnoreCase)) {
+			} else if (cmd.Equals("#Region", StringComparison.InvariantCultureIgnoreCase)) {
+				cmd = "#region";
+			} else if (cmd.Equals("#If", StringComparison.InvariantCultureIgnoreCase)) {
 				if (arg.ToLowerInvariant().EndsWith(" then"))
 					arg = arg.Substring(0, arg.Length - 5);
 			}
@@ -54,6 +56,7 @@ namespace ICSharpCode.NRefactory
 			string arg = dir.Arg;
 			switch (cmd) {
 				case "#region":
+					cmd = "#Region";
 					if (!arg.StartsWith("\"")) {
 						arg = "\"" + arg.Trim() + "\"";
 					}
diff --git a/src/Main/Base/Project/Src/Services/ParserService/ParserService.cs b/src/Main/Base/Project/Src/Services/ParserService/ParserService.cs
index 63f3ffd9af..b3285a17fb 100644
--- a/src/Main/Base/Project/Src/Services/ParserService/ParserService.cs
+++ b/src/Main/Base/Project/Src/Services/ParserService/ParserService.cs
@@ -405,22 +405,26 @@ namespace ICSharpCode.Core
 		static void CreateDefaultProjectContent()
 		{
 			LoggingService.Info("Creating default project content");
-			LoggingService.Debug("Stacktrace is:\n" + Environment.StackTrace);
+			//LoggingService.Debug("Stacktrace is:\n" + Environment.StackTrace);
 			defaultProjectContent = new DefaultProjectContent();
 			defaultProjectContent.ReferencedContents.Add(ProjectContentRegistry.Mscorlib);
-			string[] defaultReferences = new string[] {
-				"System",
-				"System.Data",
-				"System.Drawing",
-				"System.Windows.Forms",
-				"System.XML",
-				"Microsoft.VisualBasic",
-			};
+			Thread t = new Thread(new ThreadStart(CreateDefaultProjectContentReferences));
+			t.IsBackground = true;
+			t.Priority = ThreadPriority.BelowNormal;
+			t.Name = "CreateDefaultPC";
+			t.Start();
+		}
+		
+		static void CreateDefaultProjectContentReferences()
+		{
+			IList<string> defaultReferences = AddInTree.BuildItems<string>("/SharpDevelop/Services/ParserService/SingleFileGacReferences", null, false);
 			foreach (string defaultReference in defaultReferences) {
 				ReferenceProjectItem item = new ReferenceProjectItem(null, defaultReference);
 				IProjectContent pc = ParserService.GetProjectContentForReference(item);
 				if (pc != null) {
-					defaultProjectContent.ReferencedContents.Add(pc);
+					lock (defaultProjectContent.ReferencedContents) {
+						defaultProjectContent.ReferencedContents.Add(pc);
+					}
 				}
 			}
 			if (WorkbenchSingleton.Workbench != null) {