diff --git a/docs/reference/gtk/tmpl/gtknotebook.sgml b/docs/reference/gtk/tmpl/gtknotebook.sgml
index 0dc90496af..93e616af09 100644
--- a/docs/reference/gtk/tmpl/gtknotebook.sgml
+++ b/docs/reference/gtk/tmpl/gtknotebook.sgml
@@ -26,9 +26,14 @@ The GtkNoteboopk implementation of the GtkBuildable interface
supports placing children into tabs by specifying "tab" as the
"type" attribute of a <child> element. Note that the content
of the tab must be created before the tab can be filled.
-A tab child can be specified without specifying a <child>
+A tab child can be specified without specifying a <child>
type attribute.
+
+To add a child widget in the notebooks action area, specify
+"action-start" or "action-end" as the "type" attribute of the <child>
+element.
+
A UI definition fragment with GtkNotebook