+private:
+ /// This exists to make disconnecting signals easier
+ class DataObserver: public sigc::trackable
+ {
+ private:
+ List &list;
+
+ public:
+ DataObserver(List &);
+
+ void item_added(unsigned);
+ void item_removed(unsigned);
+ void cleared();
+ void refresh_strings();
+ };
+
+public:
+ sigc::signal<void, unsigned> signal_item_selected;