diff --git a/clutter/clutter-binding-pool.h b/clutter/clutter-binding-pool.h
index 281c055d6..cdba0378e 100644
--- a/clutter/clutter-binding-pool.h
+++ b/clutter/clutter-binding-pool.h
@@ -54,6 +54,7 @@ typedef struct _ClutterBindingPoolClass ClutterBindingPoolClass;
  * @action_name: the name of the action
  * @key_val: the key symbol
  * @modifiers: bitmask of the modifier flags
+ * @user_data: data passed to the function
  *
  * The prototype for the callback function registered with
  * clutter_binding_pool_install_action() and invoked by