static void AddGlobalNamespaceImport (MonoDevelop.Ide.Editor.TextEditor editor, DocumentContext context, string nsName)
		{
			var parsedDocument = context.ParsedDocument;
			var unit = parsedDocument.GetAst<SemanticModel> ();
			if (unit == null)
				return;

			int offset = SearchUsingInsertionPoint (unit.SyntaxTree.GetRoot ());

			var text = new StringBuilder ();
			text.Append ("using ");
			text.Append (nsName);
			text.Append (";");
			text.Append (editor.EolMarker);

			editor.InsertText (offset, text.ToString ());
		}