Index: Core/src/AddIns/DisplayBindings/SourceEditor/Services/SourceViewService.cs
===================================================================
--- Core/src/AddIns/DisplayBindings/SourceEditor/Services/SourceViewService.cs  (revision 2427)
+++ Core/src/AddIns/DisplayBindings/SourceEditor/Services/SourceViewService.cs  (working copy)
@@ -57,7 +57,7 @@
                                                        sts.Italic = bool.Parse (reader.GetAttribute ("italic"));
                                                        sts.Underline = bool.Parse (reader.GetAttribute ("underline"));
                                                        sts.Strikethrough = bool.Parse (reader.GetAttribute ("strikethrough"));
-                                                       sts.IsDefault = bool.Parse (reader.GetAttribute ("is_default"));
+                                                       sts.IsDefault = bool.Parse (reader.GetAttribute ("is_default")==null ? "false" : "true");
                                                        ParseColor (reader.GetAttribute ("foreground"), ref sts.Foreground);
                                                        ParseColor (reader.GetAttribute ("background"), ref sts.Background);
                                                        lang.SetTagStyle (name, sts);