[gtkmm] Add TODO

[Murray Cumming <murrayc src gnome org>]

commit a0f6721ca54a6be5d57c3e0affb1ce86aaa3301b
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Oct 5 10:02:21 2011 +0200

    Add TODO

 gtk/src/printoperation.hg |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/src/printoperation.hg b/gtk/src/printoperation.hg
index 4a392bb..8d576e2 100644
--- a/gtk/src/printoperation.hg
+++ b/gtk/src/printoperation.hg
@@ -96,7 +96,9 @@ public:
 
   PrintOperationResult run(PrintOperationAction action = PRINT_OPERATION_ACTION_PRINT_DIALOG);
 
+  //TODO: parent can be null.
   _WRAP_METHOD(PrintOperationResult run(PrintOperationAction action, Window& parent), gtk_print_operation_run, errthrow)
+
   _WRAP_METHOD(PrintStatus get_status() const, gtk_print_operation_get_status)
   _WRAP_METHOD(Glib::ustring get_status_string() const, gtk_print_operation_get_status_string)
   _WRAP_METHOD(void cancel(), gtk_print_operation_cancel)