https://bugzilla.gnome.org/show_bug.cgi?id=684667
/**
* AtkObject::children-changed:
* @atkobject: the object which received the signal.
- * @arg1: The index of the added or removed child
+ * @arg1: The index of the added or removed child. The value can be
+ * -1. This is used if the value is not known by the implementor
+ * when the child is added or irrelevant.
* @arg2: A gpointer to the child AtkObject which was added or removed
*
* The signal "children-changed" is emitted when a child is added or