diff --git a/gtk/gtkspinbutton.c b/gtk/gtkspinbutton.c
index 2a32e131e6..d698a2940e 100644
--- a/gtk/gtkspinbutton.c
+++ b/gtk/gtkspinbutton.c
@@ -433,6 +433,14 @@ gtk_spin_button_class_init (GtkSpinButtonClass *class)
                                     PROP_ORIENTATION,
                                     "orientation");
 
+  /**
+   * GtkSpinButton:shadow-type:
+   *
+   * Style of bevel around the sping button.
+   *
+   * Deprecated: 3.20: Use CSS to determine the style of the border;
+   *     the value of this syyle property is ignored.
+   */
   gtk_widget_class_install_style_property (widget_class,
                                            g_param_spec_enum ("shadow-type",
                                                               P_("Shadow Type"),