diff --git a/src/gcal-manager.h b/src/gcal-manager.h
index 8783d157..325d72ad 100644
--- a/src/gcal-manager.h
+++ b/src/gcal-manager.h
@@ -46,6 +46,7 @@ struct _GcalManagerClass
   GObjectClass parent_class;
 
   /* signals */
+  void (*source_activate)  (GcalManager *manager, ESource *source, gboolean active);
   void (*source_added)  (GcalManager *manager, ESource *source);
   void (*source_removed)  (GcalManager *manager, ESource *source);
 };