diff --git a/gtk/gtkaccellabel.c b/gtk/gtkaccellabel.c
index e0482b1..19e02ca 100644
--- a/gtk/gtkaccellabel.c
+++ b/gtk/gtkaccellabel.c
@@ -296,7 +296,7 @@ gtk_accel_label_finalize (GObject *object)
  * Fetches the widget monitored by this accelerator label. See
  * gtk_accel_label_set_accel_widget().
  *
- * Returns: (transfer none): the object monitored by the accelerator label, or %NULL.
+ * Returns: (transfer none) (allow-none): the object monitored by the accelerator label, or %NULL.
  **/
 GtkWidget*
 gtk_accel_label_get_accel_widget (GtkAccelLabel *accel_label)
diff --git a/gtk/gtkaccessible.c b/gtk/gtkaccessible.c
index 8e85b31..62ee3bf 100644
--- a/gtk/gtkaccessible.c
+++ b/gtk/gtkaccessible.c
@@ -72,7 +72,7 @@ gtk_accessible_set_widget (GtkAccessible *accessible,
  * Gets the #GtkWidget corresponding to the #GtkAccessible. The returned widget
  * does not have a reference added, so you do not need to unref it.
  *
- * Returns: (transfer none): pointer to the #GtkWidget corresponding to
+ * Returns: (transfer none) (allow-none): pointer to the #GtkWidget corresponding to
  *   the #GtkAccessible, or %NULL.
  *
  * Since: 2.22
diff --git a/gtk/gtkaction.c b/gtk/gtkaction.c
index ff4e751..e5850cc 100644
--- a/gtk/gtkaction.c
+++ b/gtk/gtkaction.c
@@ -1041,7 +1041,7 @@ gtk_action_get_proxies (GtkAction *action)
  * Returns the #GtkAction that @widget is a proxy for. 
  * See also gtk_action_get_proxies().
  *
- * Returns: the action that a widget is a proxy for, or
+ * Returns: (allow-none): the action that a widget is a proxy for, or
  *  %NULL, if it is not attached to an action.
  *
  * Since: 2.10
@@ -1814,7 +1814,7 @@ gtk_action_set_accel_path (GtkAction   *action,
  *
  * Since: 2.6
  *
- * Returns: the accel path for this action, or %NULL
+ * Returns: (allow-none): the accel path for this action, or %NULL
  *   if none is set. The returned string is owned by GTK+ 
  *   and must not be freed or modified.
  */
@@ -1944,7 +1944,7 @@ gtk_action_disconnect_accelerator (GtkAction *action)
  * item or the toolbar item it creates, this function returns an
  * instance of that menu.
  *
- * Return value: (transfer none): the menu item provided by the
+ * Return value: (transfer none) (allow-none): the menu item provided by the
  *               action, or %NULL.
  *
  * Since: 2.12
diff --git a/gtk/gtkactiongroup.c b/gtk/gtkactiongroup.c
index 81078e6..11c9221 100644
--- a/gtk/gtkactiongroup.c
+++ b/gtk/gtkactiongroup.c
@@ -731,7 +731,7 @@ gtk_action_group_set_visible (GtkActionGroup *action_group,
  *
  * Looks up an action in the action group by name.
  *
- * Returns: (transfer none): the action, or %NULL if no action by that name exists
+ * Returns: (transfer none) (allow-none): the action, or %NULL if no action by that name exists
  *
  * Since: 2.4
  */
diff --git a/gtk/gtkassistant.c b/gtk/gtkassistant.c
index 031329d..a7c63bc 100644
--- a/gtk/gtkassistant.c
+++ b/gtk/gtkassistant.c
@@ -1645,7 +1645,7 @@ gtk_assistant_get_n_pages (GtkAssistant *assistant)
  *
  * Returns the child widget contained in page number @page_num.
  *
- * Return value: (transfer none): The child widget, or %NULL
+ * Return value: (transfer none) (allow-none): The child widget, or %NULL
  *     if @page_num is out of bounds.
  *
  * Since: 2.10
@@ -2080,7 +2080,7 @@ gtk_assistant_set_page_header_image (GtkAssistant *assistant,
  *
  * Gets the header image for @page.
  *
- * Return value: (transfer none): the header image for @page, or %NULL
+ * Return value: (transfer none) (allow-none): the header image for @page, or %NULL
  *     if there's no header image for the page.
  *
  * Since: 2.10
@@ -2160,7 +2160,7 @@ gtk_assistant_set_page_side_image (GtkAssistant *assistant,
  *
  * Gets the header image for @page.
  *
- * Return value: (transfer none): the side image for @page, or %NULL
+ * Return value: (transfer none) (allow-none): the side image for @page, or %NULL
  *     if there's no side image for the page.
  *
  * Since: 2.10
diff --git a/gtk/gtkbindings.c b/gtk/gtkbindings.c
index 0519e58..31ed6b8 100644
--- a/gtk/gtkbindings.c
+++ b/gtk/gtkbindings.c
@@ -636,7 +636,7 @@ gtk_binding_set_by_class (gpointer object_class)
  * either be a name used for gtk_binding_set_new() or the type name of
  * a class used in gtk_binding_set_by_class().
  *
- * Return value: (transfer none): %NULL or the specified binding set
+ * Return value: (transfer none) (allow-none): %NULL or the specified binding set
  */
 GtkBindingSet*
 gtk_binding_set_find (const gchar *set_name)
diff --git a/gtk/gtkbuilder.c b/gtk/gtkbuilder.c
index 0ef6087..77f178d 100644
--- a/gtk/gtkbuilder.c
+++ b/gtk/gtkbuilder.c
@@ -871,7 +871,7 @@ gtk_builder_add_objects_from_string (GtkBuilder   *builder,
  * Gets the object named @name. Note that this function does not
  * increment the reference count of the returned object. 
  *
- * Return value: (transfer none): the object named @name or %NULL if
+ * Return value: (transfer none) (allow-none): the object named @name or %NULL if
  *    it could not be found in the object tree.
  *
  * Since: 2.12
diff --git a/gtk/gtkbutton.c b/gtk/gtkbutton.c
index 68e8ea7..48e007d 100644
--- a/gtk/gtkbutton.c
+++ b/gtk/gtkbutton.c
@@ -2241,7 +2241,7 @@ gtk_button_set_image (GtkButton *button,
  * This may have been explicitly set by gtk_button_set_image()
  * or constructed by gtk_button_new_from_stock().
  *
- * Return value: (transfer none): a #GtkWidget or %NULL in case there is no image
+ * Return value: (transfer none) (allow-none): a #GtkWidget or %NULL in case there is no image
  *
  * Since: 2.6
  */
diff --git a/gtk/gtkcalendar.h b/gtk/gtkcalendar.h
index b75fdeb..5f70c37 100644
--- a/gtk/gtkcalendar.h
+++ b/gtk/gtkcalendar.h
@@ -93,7 +93,7 @@ typedef enum
  *
  * Since: 2.14
  *
- * Return value: Newly allocated string with Pango markup with details
+ * Return value: (allow-none): Newly allocated string with Pango markup with details
  * for the specified day, or %NULL.
  */
 typedef gchar* (*GtkCalendarDetailFunc) (GtkCalendar *calendar,
diff --git a/gtk/gtkcellrenderer.c b/gtk/gtkcellrenderer.c
index dcce8dc..b575031 100644
--- a/gtk/gtkcellrenderer.c
+++ b/gtk/gtkcellrenderer.c
@@ -640,7 +640,7 @@ gtk_cell_renderer_activate (GtkCellRenderer      *cell,
  *
  * Passes an activate event to the cell renderer for possible processing.
  *
- * Return value: (transfer none): A new #GtkCellEditable, or %NULL
+ * Return value: (transfer none) (allow-none): A new #GtkCellEditable, or %NULL
  **/
 GtkCellEditable *
 gtk_cell_renderer_start_editing (GtkCellRenderer      *cell,
diff --git a/gtk/gtkcellview.c b/gtk/gtkcellview.c
index 4b26c05..64981f1 100644
--- a/gtk/gtkcellview.c
+++ b/gtk/gtkcellview.c
@@ -902,7 +902,7 @@ gtk_cell_view_set_model (GtkCellView  *cell_view,
  * Returns the model for @cell_view. If no model is used %NULL is
  * returned.
  *
- * Returns: (transfer none): a #GtkTreeModel used or %NULL
+ * Returns: (transfer none) (allow-none): a #GtkTreeModel used or %NULL
  *
  * Since: 2.16
  **/
@@ -958,7 +958,7 @@ gtk_cell_view_set_displayed_row (GtkCellView *cell_view,
  * displayed row. If no row is currently displayed, 
  * %NULL is returned.
  *
- * Returns: the currently displayed row or %NULL
+ * Returns: (allow-none): the currently displayed row or %NULL
  *
  * Since: 2.6
  */
diff --git a/gtk/gtkclipboard.c b/gtk/gtkclipboard.c
index 9b17f6f..64bf7f2 100644
--- a/gtk/gtkclipboard.c
+++ b/gtk/gtkclipboard.c
@@ -649,7 +649,7 @@ gtk_clipboard_set_with_owner (GtkClipboard          *clipboard,
  * gtk_clipboard_clear() has not subsequently called, returns the owner set 
  * by gtk_clipboard_set_with_owner().
  * 
- * Return value: (transfer none): the owner of the clipboard, if any; otherwise %NULL.
+ * Return value: (transfer none) (allow-none): the owner of the clipboard, if any; otherwise %NULL.
  **/
 GObject *
 gtk_clipboard_get_owner (GtkClipboard *clipboard)
@@ -1295,7 +1295,7 @@ clipboard_received_func (GtkClipboard     *clipboard,
  * This function waits for the data to be received using the main 
  * loop, so events, timeouts, etc, may be dispatched during the wait.
  * 
- * Return value: a newly-allocated #GtkSelectionData object or %NULL
+ * Return value: (allow-none): a newly-allocated #GtkSelectionData object or %NULL
  *               if retrieving the given target failed. If non-%NULL,
  *               this value must be freed with gtk_selection_data_free() 
  *               when you are finished with it.
@@ -1348,7 +1348,7 @@ clipboard_text_received_func (GtkClipboard *clipboard,
  * the data to be received using the main loop, so events,
  * timeouts, etc, may be dispatched during the wait.
  * 
- * Return value: a newly-allocated UTF-8 string which must
+ * Return value: (allow-none): a newly-allocated UTF-8 string which must
  *               be freed with g_free(), or %NULL if retrieving
  *               the selection data failed. (This could happen
  *               for various reasons, in particular if the
@@ -1474,7 +1474,7 @@ clipboard_image_received_func (GtkClipboard *clipboard,
  * the data to be received using the main loop, so events,
  * timeouts, etc, may be dispatched during the wait.
  * 
- * Return value: (transfer full): a newly-allocated #GdkPixbuf object which must
+ * Return value: (transfer full) (allow-none): a newly-allocated #GdkPixbuf object which must
  *               be disposed with g_object_unref(), or %NULL if 
  *               retrieving the selection data failed. (This 
  *               could happen for various reasons, in particular 
diff --git a/gtk/gtkcontainer.c b/gtk/gtkcontainer.c
index 9aaa7d9..68b6219 100644
--- a/gtk/gtkcontainer.c
+++ b/gtk/gtkcontainer.c
@@ -1624,7 +1624,7 @@ gtk_container_set_focus_child (GtkContainer *container,
  * currently focused widget. That can be obtained by calling
  * gtk_window_get_focus().
  *
- * Returns: (transfer none): The child widget which will receive the
+ * Returns: (transfer none) (allow-none): The child widget which will receive the
  *          focus inside @container when the @conatiner is focussed,
  *          or %NULL if none is set.
  *
@@ -2532,7 +2532,7 @@ gtk_container_set_focus_vadjustment (GtkContainer  *container,
  * Retrieves the vertical focus adjustment for the container. See
  * gtk_container_set_focus_vadjustment().
  *
- * Return value: (transfer none): the vertical focus adjustment, or %NULL if
+ * Return value: (transfer none) (allow-none): the vertical focus adjustment, or %NULL if
  *   none has been set.
  **/
 GtkAdjustment *
@@ -2587,7 +2587,7 @@ gtk_container_set_focus_hadjustment (GtkContainer  *container,
  * Retrieves the horizontal focus adjustment for the container. See
  * gtk_container_set_focus_hadjustment ().
  *
- * Return value: (transfer none): the horizontal focus adjustment, or %NULL if
+ * Return value: (transfer none) (allow-none): the horizontal focus adjustment, or %NULL if
  *   none has been set.
  **/
 GtkAdjustment *
diff --git a/gtk/gtkdialog.c b/gtk/gtkdialog.c
index a2756f6..04e1e9e 100644
--- a/gtk/gtkdialog.c
+++ b/gtk/gtkdialog.c
@@ -1132,7 +1132,7 @@ _gtk_dialog_set_ignore_separator (GtkDialog *dialog,
  * Gets the widget button that uses the given response ID in the action area
  * of a dialog.
  *
- * Returns: (transfer none):the @widget button that uses the given @response_id, or %NULL.
+ * Returns: (transfer none) (allow-none): the @widget button that uses the given @response_id, or %NULL.
  *
  * Since: 2.20
  */
diff --git a/gtk/gtkdnd.c b/gtk/gtkdnd.c
index 144ec2b..545336f 100644
--- a/gtk/gtkdnd.c
+++ b/gtk/gtkdnd.c
@@ -1000,7 +1000,7 @@ gtk_drag_get_data (GtkWidget      *widget,
  *
  * Determines the source widget for a drag.
  *
- * Return value: (transfer none): if the drag is occurring
+ * Return value: (transfer none) (allow-none): if the drag is occurring
  *     within a single application, a pointer to the source widget.
  *     Otherwise, %NULL.
  */
@@ -1367,7 +1367,7 @@ gtk_drag_dest_unset (GtkWidget *widget)
  * Returns the list of targets this widget can accept from
  * drag-and-drop.
  * 
- * Return value: (transfer none): the #GtkTargetList, or %NULL if none
+ * Return value: (transfer none) (allow-none): the #GtkTargetList, or %NULL if none
  **/
 GtkTargetList*
 gtk_drag_dest_get_target_list (GtkWidget *widget)
@@ -2649,7 +2649,7 @@ gtk_drag_source_unset (GtkWidget        *widget)
  * Gets the list of targets this widget can provide for
  * drag-and-drop.
  *
- * Return value: (transfer none): the #GtkTargetList, or %NULL if none
+ * Return value: (transfer none) (allow-none): the #GtkTargetList, or %NULL if none
  *
  * Since: 2.4
  **/
diff --git a/gtk/gtkentry.c b/gtk/gtkentry.c
index f2a6328..a206cc8 100644
--- a/gtk/gtkentry.c
+++ b/gtk/gtkentry.c
@@ -7363,7 +7363,7 @@ gtk_entry_set_inner_border (GtkEntry        *entry,
  * This function returns the entry's #GtkEntry:inner-border property. See
  * gtk_entry_set_inner_border() for more information.
  *
- * Return value: (transfer none): the entry's #GtkBorder, or %NULL if none was set.
+ * Return value: (transfer none) (allow-none): the entry's #GtkBorder, or %NULL if none was set.
  *
  * Since: 2.10
  **/
@@ -7925,7 +7925,7 @@ gtk_entry_get_icon_activatable (GtkEntry             *entry,
  * method will work regardless of whether the icon was set using a
  * #GdkPixbuf, a #GIcon, a stock item, or an icon name.
  *
- * Returns: (transfer none): A #GdkPixbuf, or %NULL if no icon is
+ * Returns: (transfer none) (allow-none): A #GdkPixbuf, or %NULL if no icon is
  *     set for this position.
  *
  * Since: 2.16
@@ -7960,7 +7960,7 @@ gtk_entry_get_icon_pixbuf (GtkEntry             *entry,
  * no icon or if the icon was set by some other method (e.g., by
  * stock, pixbuf, or icon name).
  *
- * Returns: (transfer none): A #GIcon, or %NULL if no icon is set
+ * Returns: (transfer none) (allow-none): A #GIcon, or %NULL if no icon is set
  *     or if the icon is not a #GIcon
  *
  * Since: 2.16
@@ -7993,8 +7993,8 @@ gtk_entry_get_icon_gicon (GtkEntry             *entry,
  * no icon or if the icon was set by some other method (e.g., by
  * pixbuf, icon name or gicon).
  *
- * Returns: A stock id, or %NULL if no icon is set or if the icon
- *          wasn't set from a stock id
+ * Returns: (allow-none): A stock id, or %NULL if no icon is set or if the icon
+ *                        wasn't set from a stock id
  *
  * Since: 2.16
  */
@@ -8026,8 +8026,8 @@ gtk_entry_get_icon_stock (GtkEntry             *entry,
  * no icon or if the icon was set by some other method (e.g., by
  * pixbuf, stock or gicon).
  *
- * Returns: An icon name, or %NULL if no icon is set or if the icon
- *          wasn't set from an icon name
+ * Returns: (allow-none): An icon name, or %NULL if no icon is set or if the icon
+ *                        wasn't set from an icon name
  *
  * Since: 2.16
  */
@@ -8350,7 +8350,7 @@ ensure_has_tooltip (GtkEntry *entry)
  * Gets the contents of the tooltip on the icon at the specified 
  * position in @entry.
  * 
- * Returns: the tooltip text, or %NULL. Free the returned string
+ * Returns: (allow-none): the tooltip text, or %NULL. Free the returned string
  *     with g_free() when done.
  * 
  * Since: 2.16
@@ -8433,7 +8433,7 @@ gtk_entry_set_icon_tooltip_text (GtkEntry             *entry,
  * Gets the contents of the tooltip on the icon at the specified 
  * position in @entry.
  * 
- * Returns: the tooltip text, or %NULL. Free the returned string
+ * Returns: (allow-none): the tooltip text, or %NULL. Free the returned string
  *     with g_free() when done.
  * 
  * Since: 2.16
@@ -9879,7 +9879,7 @@ gtk_entry_set_cursor_hadjustment (GtkEntry      *entry,
  * Retrieves the horizontal cursor adjustment for the entry. 
  * See gtk_entry_set_cursor_hadjustment().
  *
- * Return value: (transfer none): the horizontal cursor adjustment, or %NULL
+ * Return value: (transfer none) (allow-none): the horizontal cursor adjustment, or %NULL
  *   if none has been set.
  *
  * Since: 2.12
diff --git a/gtk/gtkentrycompletion.c b/gtk/gtkentrycompletion.c
index 2fa7b56..85e2510 100644
--- a/gtk/gtkentrycompletion.c
+++ b/gtk/gtkentrycompletion.c
@@ -1066,7 +1066,7 @@ gtk_entry_completion_set_model (GtkEntryCompletion *completion,
  * Returns the model the #GtkEntryCompletion is using as data source.
  * Returns %NULL if the model is unset.
  *
- * Return value: (transfer none): A #GtkTreeModel, or %NULL if none
+ * Return value: (transfer none) (allow-none): A #GtkTreeModel, or %NULL if none
  *     is currently being used.
  *
  * Since: 2.4
diff --git a/gtk/gtkexpander.c b/gtk/gtkexpander.c
index 879f96f..2e2f439 100644
--- a/gtk/gtkexpander.c
+++ b/gtk/gtkexpander.c
@@ -1758,7 +1758,7 @@ gtk_expander_set_label_widget (GtkExpander *expander,
  * Retrieves the label widget for the frame. See
  * gtk_expander_set_label_widget().
  *
- * Return value: (transfer none): the label widget,
+ * Return value: (transfer none) (allow-none): the label widget,
  *     or %NULL if there is none.
  *
  * Since: 2.4
diff --git a/gtk/gtkfilechooser.c b/gtk/gtkfilechooser.c
index 8dd0dec..8bea492 100644
--- a/gtk/gtkfilechooser.c
+++ b/gtk/gtkfilechooser.c
@@ -1161,7 +1161,7 @@ gtk_file_chooser_get_create_folders (GtkFileChooser *chooser)
  * If the file chooser is in folder mode, this function returns the selected
  * folder.
  * 
- * Return value: (type filename): The currently selected filename, or %NULL
+ * Return value: (type filename) (allow-none): The currently selected filename, or %NULL
  *  if no file is selected, or the selected file can't
  *  be represented with a local filename. Free with g_free().
  *
@@ -1414,7 +1414,7 @@ gtk_file_chooser_set_current_folder (GtkFileChooser *chooser,
  * currently-selected folder in that mode, use gtk_file_chooser_get_uri() as the
  * usual way to get the selection.
  * 
- * Return value: (type filename): the full path of the current folder,
+ * Return value: (type filename) (allow-none): the full path of the current folder,
  * or %NULL if the current path cannot be represented as a local
  * filename.  Free with g_free().  This function will also return
  * %NULL if the file chooser was unable to load the last folder that
@@ -1479,7 +1479,7 @@ gtk_file_chooser_set_current_name  (GtkFileChooser *chooser,
  * If the file chooser is in folder mode, this function returns the selected
  * folder.
  * 
- * Return value: The currently selected URI, or %NULL
+ * Return value: (allow-none): The currently selected URI, or %NULL
  *  if no file is selected. If gtk_file_chooser_set_local_only() is set to %TRUE
  * (the default) a local URI will be returned for any FUSE locations.
  * Free with g_free()
@@ -1729,7 +1729,7 @@ gtk_file_chooser_set_current_folder_uri (GtkFileChooser *chooser,
  * currently-selected folder in that mode, use gtk_file_chooser_get_uri() as the
  * usual way to get the selection.
  * 
- * Return value: the URI for the current folder.  Free with g_free().  This
+ * Return value: (allow-none): the URI for the current folder.  Free with g_free().  This
  * function will also return %NULL if the file chooser was unable to load the
  * last folder that was requested from it; for example, as would be for calling
  * gtk_file_chooser_set_current_folder_uri() on a nonexistent folder.
@@ -2021,7 +2021,7 @@ gtk_file_chooser_set_preview_widget (GtkFileChooser *chooser,
  * Gets the current preview widget; see
  * gtk_file_chooser_set_preview_widget().
  *
- * Return value: (transfer none): the current preview widget, or %NULL
+ * Return value: (transfer none) (allow-none): the current preview widget, or %NULL
  *
  * Since: 2.4
  **/
@@ -2143,7 +2143,7 @@ gtk_file_chooser_get_use_preview_label (GtkFileChooser *chooser)
  * Gets the #GFile that should be previewed in a custom preview
  * Internal function, see gtk_file_chooser_get_preview_uri().
  *
- * Return value: (transfer full): the #GFile for the file to preview,
+ * Return value: (transfer full) (allow-none): the #GFile for the file to preview,
  *     or %NULL if no file is selected. Free with g_object_unref().
  *
  * Since: 2.14
@@ -2213,7 +2213,7 @@ _gtk_file_chooser_remove_shortcut_folder (GtkFileChooser  *chooser,
  * Gets the filename that should be previewed in a custom preview
  * widget. See gtk_file_chooser_set_preview_widget().
  * 
- * Return value: (type filename): the filename to preview, or %NULL if
+ * Return value: (type filename) (allow-none): the filename to preview, or %NULL if
  *  no file is selected, or if the selected file cannot be represented
  *  as a local filename. Free with g_free()
  *
@@ -2244,7 +2244,7 @@ gtk_file_chooser_get_preview_filename (GtkFileChooser *chooser)
  * Gets the URI that should be previewed in a custom preview
  * widget. See gtk_file_chooser_set_preview_widget().
  * 
- * Return value: the URI for the file to preview, or %NULL if no file is
+ * Return value: (allow-none): the URI for the file to preview, or %NULL if no file is
  * selected. Free with g_free().
  *
  * Since: 2.4
@@ -2292,7 +2292,7 @@ gtk_file_chooser_set_extra_widget (GtkFileChooser *chooser,
  * Gets the current preview widget; see
  * gtk_file_chooser_set_extra_widget().
  *
- * Return value: (transfer none): the current extra widget, or %NULL
+ * Return value: (transfer none) (allow-none): the current extra widget, or %NULL
  *
  * Since: 2.4
  **/
@@ -2408,7 +2408,7 @@ gtk_file_chooser_set_filter (GtkFileChooser *chooser,
  *
  * Gets the current filter; see gtk_file_chooser_set_filter().
  *
- * Return value: (transfer none): the current filter, or %NULL
+ * Return value: (transfer none) (allow-none): the current filter, or %NULL
  *
  * Since: 2.4
  **/
@@ -2504,7 +2504,7 @@ gtk_file_chooser_remove_shortcut_folder (GtkFileChooser    *chooser,
  * Queries the list of shortcut folders in the file chooser, as set by
  * gtk_file_chooser_add_shortcut_folder().
  *
- * Return value: (element-type filename) (transfer full): A list of
+ * Return value: (element-type filename) (transfer full) (allow-none): A list of
  * folder filenames, or %NULL if there are no shortcut folders.  Free
  * the returned list with g_slist_free(), and the filenames with
  * g_free().
@@ -2602,7 +2602,7 @@ gtk_file_chooser_remove_shortcut_folder_uri (GtkFileChooser    *chooser,
  * Queries the list of shortcut folders in the file chooser, as set by
  * gtk_file_chooser_add_shortcut_folder_uri().
  *
- * Return value: (element-type utf8) (transfer full): A list of folder
+ * Return value: (element-type utf8) (transfer full) (allow-none): A list of folder
  * URIs, or %NULL if there are no shortcut folders.  Free the returned
  * list with g_slist_free(), and the URIs with g_free().
  *
diff --git a/gtk/gtkfilefilter.c b/gtk/gtkfilefilter.c
index 5a6b411..b4b6a45 100644
--- a/gtk/gtkfilefilter.c
+++ b/gtk/gtkfilefilter.c
@@ -182,7 +182,7 @@ gtk_file_filter_set_name (GtkFileFilter *filter,
  * 
  * Gets the human-readable name for the filter. See gtk_file_filter_set_name().
  * 
- * Return value: The human-readable name of the filter,
+ * Return value: (allow-none): The human-readable name of the filter,
  *   or %NULL. This value is owned by GTK+ and must not
  *   be modified or freed.
  * 
diff --git a/gtk/gtkfilesystemmodel.c b/gtk/gtkfilesystemmodel.c
index 1ba14d3..8b6fccf 100644
--- a/gtk/gtkfilesystemmodel.c
+++ b/gtk/gtkfilesystemmodel.c
@@ -1585,8 +1585,8 @@ _gtk_file_system_model_get_file (GtkFileSystemModel *model,
  * the value and spend a considerable amount of time in iterator 
  * lookups. Both of which are slow.
  *
- * Returns: a pointer to the actual value as stored in @model or %NULL
- *          if no value available yet.
+ * Returns: (allow-none): a pointer to the actual value as stored in @model or %NULL
+ *                        if no value available yet.
  **/
 const GValue *
 _gtk_file_system_model_get_value (GtkFileSystemModel *model,
diff --git a/gtk/gtkfontsel.c b/gtk/gtkfontsel.c
index 5bfb5b3..51dca83 100644
--- a/gtk/gtkfontsel.c
+++ b/gtk/gtkfontsel.c
@@ -1370,7 +1370,7 @@ gtk_font_selection_get_font (GtkFontSelection *fontsel)
  * "Helvetica Bold Italic 12". Use pango_font_description_equal()
  * if you want to compare two font descriptions.
  * 
- * Return value: A string with the name of the current font, or %NULL if 
+ * Return value: (allow-none): A string with the name of the current font, or %NULL if 
  *     no font is selected. You must free this string with g_free().
  */
 gchar *
@@ -1787,7 +1787,7 @@ gtk_font_selection_dialog_buildable_get_internal_child (GtkBuildable *buildable,
  * to "Helvetica Bold Italic 12".  Use pango_font_description_equal()
  * if you want to compare two font descriptions.
  * 
- * Return value: A string with the name of the current font, or %NULL if no 
+ * Return value: (allow-none): A string with the name of the current font, or %NULL if no 
  *     font is selected. You must free this string with g_free().
  */
 gchar*
@@ -1804,7 +1804,7 @@ gtk_font_selection_dialog_get_font_name (GtkFontSelectionDialog *fsd)
  *
  * Gets the currently-selected font.
  *
- * Return value: the #GdkFont from the #GtkFontSelection for the
+ * Return value: (allow-none): the #GdkFont from the #GtkFontSelection for the
  *     currently selected font in the dialog, or %NULL if no font is selected
  *
  * Deprecated: 2.0: Use gtk_font_selection_dialog_get_font_name() instead.
diff --git a/gtk/gtkframe.c b/gtk/gtkframe.c
index 93454f9..8e4e27f 100644
--- a/gtk/gtkframe.c
+++ b/gtk/gtkframe.c
@@ -339,7 +339,7 @@ gtk_frame_set_label (GtkFrame *frame,
  * for the label widget if a non-%NULL argument was passed
  * to gtk_frame_new().)
  * 
- * Return value: the text in the label, or %NULL if there
+ * Return value: (allow-none): the text in the label, or %NULL if there
  *               was no label widget or the lable widget was not
  *               a #GtkLabel. This string is owned by GTK+ and
  *               must not be modified or freed.
@@ -408,7 +408,7 @@ gtk_frame_set_label_widget (GtkFrame  *frame,
  * Retrieves the label widget for the frame. See
  * gtk_frame_set_label_widget().
  *
- * Return value: (transfer none): the label widget, or %NULL if there is none.
+ * Return value: (transfer none) (allow-none): the label widget, or %NULL if there is none.
  **/
 GtkWidget *
 gtk_frame_get_label_widget (GtkFrame *frame)
diff --git a/gtk/gtkiconfactory.c b/gtk/gtkiconfactory.c
index 846714f..8380f13 100644
--- a/gtk/gtkiconfactory.c
+++ b/gtk/gtkiconfactory.c
@@ -316,7 +316,7 @@ _gtk_icon_factory_ensure_default_icons (void)
  * using this function directly, so that themes are taken into
  * account.
  *
- * Return value: (transfer none): a #GtkIconSet, or %NULL
+ * Return value: (transfer none) (allow-none): a #GtkIconSet, or %NULL
  */
 GtkIconSet *
 gtk_icon_factory_lookup_default (const gchar *stock_id)
diff --git a/gtk/gtkicontheme.c b/gtk/gtkicontheme.c
index b4ee484..af504e5 100644
--- a/gtk/gtkicontheme.c
+++ b/gtk/gtkicontheme.c
@@ -1397,7 +1397,7 @@ choose_icon (GtkIconTheme       *icon_theme,
  * gtk_icon_info_load_icon(). (gtk_icon_theme_load_icon()
  * combines these two steps if all you need is the pixbuf.)
  * 
- * Return value: a #GtkIconInfo structure containing information
+ * Return value: (allow-none): a #GtkIconInfo structure containing information
  * about the icon, or %NULL if the icon wasn't found. Free with
  * gtk_icon_info_free()
  *
@@ -1475,7 +1475,7 @@ gtk_icon_theme_lookup_icon (GtkIconTheme       *icon_theme,
  * tries them all in the given order before falling back to 
  * inherited icon themes.
  * 
- * Return value: a #GtkIconInfo structure containing information
+ * Return value: (allow-none): a #GtkIconInfo structure containing information
  * about the icon, or %NULL if the icon wasn't found. Free with
  * gtk_icon_info_free()
  *
@@ -1524,7 +1524,7 @@ gtk_icon_theme_error_quark (void)
  * returned by this function. Otherwise GTK+ may need to keep the old 
  * icon theme loaded, which would be a waste of memory.
  * 
- * Return value: (transfer full): the rendered icon; this may be a newly
+ * Return value: (transfer full) (allow-none): the rendered icon; this may be a newly
  *  created icon or a new reference to an internal icon, so you must not modify
  *  the icon. Use g_object_unref() to release your reference to the
  *  icon. %NULL if the icon isn't found.
@@ -1859,7 +1859,7 @@ gtk_icon_theme_list_contexts (GtkIconTheme *icon_theme)
  * current theme (for instance, to use when presenting
  * a list of themes to the user.)
  * 
- * Return value: the name of an example icon or %NULL.
+ * Return value: (allow-none): the name of an example icon or %NULL.
  *  Free with g_free().
  *
  * Since: 2.4
@@ -2738,7 +2738,7 @@ gtk_icon_info_get_base_size (GtkIconInfo *icon_info)
  * no filename if a builtin icon is returned; in this
  * case, you should use gtk_icon_info_get_builtin_pixbuf().
  * 
- * Return value: the filename for the icon, or %NULL
+ * Return value: (allow-none): the filename for the icon, or %NULL
  *  if gtk_icon_info_get_builtin_pixbuf() should
  *  be used instead. The return value is owned by
  *  GTK+ and should not be modified or freed.
@@ -2762,7 +2762,7 @@ gtk_icon_info_get_filename (GtkIconInfo *icon_info)
  * %GTK_ICON_LOOKUP_USE_BUILTIN to
  * gtk_icon_theme_lookup_icon().
  *
- * Return value: (transfer none): the built-in image pixbuf, or %NULL. No
+ * Return value: (transfer none) (allow-none): the built-in image pixbuf, or %NULL. No
  *  extra reference is added to the returned pixbuf, so if
  *  you want to keep it around, you must use g_object_ref().
  *  The returned image must not be modified.
@@ -3272,7 +3272,7 @@ gtk_icon_info_get_attach_points (GtkIconInfo *icon_info,
  * string to be used in place of the icon name in a user
  * visible context like a list of icons.
  * 
- * Return value: the display name for the icon or %NULL, if
+ * Return value: (allow-none): the display name for the icon or %NULL, if
  *  the icon doesn't have a specified display name. This value
  *  is owned @icon_info and must not be modified or free.
  *
@@ -3459,7 +3459,7 @@ _gtk_icon_theme_check_reload (GdkDisplay *display)
  * The icon can then be rendered into a pixbuf using
  * gtk_icon_info_load_icon().
  *
- * Return value: a #GtkIconInfo structure containing 
+ * Return value: (allow-none): a #GtkIconInfo structure containing 
  *     information about the icon, or %NULL if the icon 
  *     wasn't found. Free with gtk_icon_info_free()
  *
diff --git a/gtk/gtkiconview.c b/gtk/gtkiconview.c
index 190fec8..1cc2e3f 100644
--- a/gtk/gtkiconview.c
+++ b/gtk/gtkiconview.c
@@ -4843,7 +4843,7 @@ gtk_icon_view_convert_widget_to_bin_window_coords (GtkIconView *icon_view,
  * See gtk_icon_view_convert_widget_to_bin_window_coords() for converting
  * widget coordinates to bin_window coordinates.
  * 
- * Return value: The #GtkTreePath corresponding to the icon or %NULL
+ * Return value: (allow-none): The #GtkTreePath corresponding to the icon or %NULL
  * if no icon exists at that position.
  *
  * Since: 2.6 
@@ -5439,7 +5439,7 @@ gtk_icon_view_set_model (GtkIconView *icon_view,
  * Returns the model the #GtkIconView is based on.  Returns %NULL if the
  * model is unset.
  *
- * Return value: (transfer none): A #GtkTreeModel, or %NULL if none is
+ * Return value: (transfer none) (allow-none): A #GtkTreeModel, or %NULL if none is
  *     currently being used.
  *
  * Since: 2.6 
diff --git a/gtk/gtkimage.c b/gtk/gtkimage.c
index c35d962..850e5e7 100644
--- a/gtk/gtkimage.c
+++ b/gtk/gtkimage.c
@@ -1336,7 +1336,7 @@ gtk_image_get_image  (GtkImage   *image,
  * The caller of this function does not own a reference to the
  * returned pixbuf.
  * 
- * Return value: (transfer none): the displayed pixbuf, or %NULL if
+ * Return value: (transfer none) (allow-none): the displayed pixbuf, or %NULL if
  * the image is empty
  **/
 GdkPixbuf*
@@ -1423,7 +1423,7 @@ gtk_image_get_icon_set  (GtkImage        *image,
  * The caller of this function does not own a reference to the
  * returned animation.
  * 
- * Return value: (transfer none): the displayed animation, or %NULL if
+ * Return value: (transfer none) (allow-none): the displayed animation, or %NULL if
  * the image is empty
  **/
 GdkPixbufAnimation*
diff --git a/gtk/gtklabel.c b/gtk/gtklabel.c
index 202ee54..31f3f60 100644
--- a/gtk/gtklabel.c
+++ b/gtk/gtklabel.c
@@ -1726,7 +1726,7 @@ gtk_label_set_mnemonic_widget (GtkLabel  *label,
  * Retrieves the target of the mnemonic (keyboard shortcut) of this
  * label. See gtk_label_set_mnemonic_widget().
  *
- * Return value: (transfer none): the target of the label's mnemonic,
+ * Return value: (transfer none) (allow-none): the target of the label's mnemonic,
  *     or %NULL if none has been set and the default algorithm will be used.
  **/
 GtkWidget *
@@ -1957,7 +1957,7 @@ gtk_label_set_attributes (GtkLabel         *label,
  * effective attributes for the label, use
  * pango_layout_get_attribute (gtk_label_get_layout (label)).
  *
- * Return value: (transfer none): the attribute list, or %NULL
+ * Return value: (transfer none) (allow-none): the attribute list, or %NULL
  *     if none was set.
  **/
 PangoAttrList *
diff --git a/gtk/gtkmain.c b/gtk/gtkmain.c
index 4fb791d..a096c72 100644
--- a/gtk/gtkmain.c
+++ b/gtk/gtkmain.c
@@ -270,7 +270,7 @@ static const GDebugKey gtk_debug_keys[] = {
  * old version of gtk_check_version(), but still get loaded
  * into an application using a newer version of GTK+.
  *
- * Return value: %NULL if the GTK+ library is compatible with the
+ * Return value: (allow-none): %NULL if the GTK+ library is compatible with the
  *   given version, or a string describing the version mismatch.
  *   The returned string is owned by GTK+ and should not be modified
  *   or freed.
@@ -1899,7 +1899,7 @@ gtk_grab_add (GtkWidget *widget)
  *
  * Queries the current grab of the default window group.
  *
- * Return value: (transfer none): The widget which currently
+ * Return value: (transfer none) (allow-none): The widget which currently
  *     has the grab or %NULL if no grab is active
  */
 GtkWidget*
@@ -2310,7 +2310,7 @@ gtk_invoke_input (gpointer	    data,
  * signal. The returned event must be freed with gdk_event_free().
  * If there is no current event, the function returns %NULL.
  * 
- * Return value: (transfer full): a copy of the current event, or %NULL if no
+ * Return value: (transfer full) (allow-none): a copy of the current event, or %NULL if no
  *     current event.
  **/
 GdkEvent*
@@ -2371,7 +2371,7 @@ gtk_get_current_event_state (GdkModifierType *state)
  * returns %NULL, otherwise returns the widget that received the event
  * originally.
  * 
- * Return value: (transfer none): the widget that originally
+ * Return value: (transfer none) (allow-none): the widget that originally
  *     received @event, or %NULL
  **/
 GtkWidget*
diff --git a/gtk/gtkmenu.c b/gtk/gtkmenu.c
index fc25098..2b5c2cf 100644
--- a/gtk/gtkmenu.c
+++ b/gtk/gtkmenu.c
@@ -2172,7 +2172,7 @@ gtk_menu_set_title (GtkMenu     *menu,
  *
  * Returns the title of the menu. See gtk_menu_set_title().
  *
- * Return value: the title of the menu, or %NULL if the menu has no
+ * Return value: (allow-none): the title of the menu, or %NULL if the menu has no
  * title set on it. This string is owned by the widget and should
  * not be modified or freed.
  **/
diff --git a/gtk/gtkmenuitem.c b/gtk/gtkmenuitem.c
index 8f23b75..133b237 100644
--- a/gtk/gtkmenuitem.c
+++ b/gtk/gtkmenuitem.c
@@ -802,7 +802,7 @@ gtk_menu_item_set_submenu (GtkMenuItem *menu_item,
  * Gets the submenu underneath this menu item, if any.
  * See gtk_menu_item_set_submenu().
  *
- * Return value: (transfer none): submenu for this menu item, or %NULL if none.
+ * Return value: (transfer none) (allow-none): submenu for this menu item, or %NULL if none.
  **/
 GtkWidget *
 gtk_menu_item_get_submenu (GtkMenuItem *menu_item)
@@ -2074,7 +2074,7 @@ gtk_menu_item_set_accel_path (GtkMenuItem *menu_item,
  *
  * See gtk_menu_item_set_accel_path() for details.
  *
- * Returns: the accelerator path corresponding to this menu item's
+ * Returns: (allow-none): the accelerator path corresponding to this menu item's
  *              functionality, or %NULL if not set
  *
  * Since: 2.14
diff --git a/gtk/gtkmodules.c b/gtk/gtkmodules.c
index 50729b6..1aa6b52 100644
--- a/gtk/gtkmodules.c
+++ b/gtk/gtkmodules.c
@@ -181,7 +181,7 @@ module_build_la_path (const gchar *directory,
  * Looks for a dynamically module named @name of type @type in the standard GTK+
  *  module search path.
  * 
- * Return value: the pathname to the found module, or %NULL if it wasn't found.
+ * Return value: (allow-none): the pathname to the found module, or %NULL if it wasn't found.
  *  Free with g_free().
  **/
 gchar *
diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index 0770de6..aead822 100644
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -1005,7 +1005,7 @@ gtk_notebook_class_init (GtkNotebookClass *class)
    * The default handler uses the global window creation hook,
    * if one has been set with gtk_notebook_set_window_creation_hook().
    *
-   * Returns: (transfer none): a #GtkNotebook that @page should be
+   * Returns: (transfer none) (allow-none): a #GtkNotebook that @page should be
    *     added to, or %NULL.
    *
    * Since: 2.12
@@ -6707,7 +6707,7 @@ gtk_notebook_get_current_page (GtkNotebook *notebook)
  * 
  * Returns the child widget contained in page number @page_num.
  *
- * Return value: (transfer none): the child widget, or %NULL if @page_num is
+ * Return value: (transfer none) (allow-none): the child widget, or %NULL if @page_num is
  * out of bounds.
  **/
 GtkWidget*
@@ -7404,7 +7404,7 @@ gtk_notebook_set_tab_label_text (GtkNotebook *notebook,
  * Retrieves the text of the tab label for the page containing
  *    @child.
  *
- * Return value: the text of the tab label, or %NULL if the
+ * Return value: (allow-none): the text of the tab label, or %NULL if the
  *               tab label widget is not a #GtkLabel. The
  *               string is owned by the widget and must not
  *               be freed.
@@ -7433,7 +7433,7 @@ gtk_notebook_get_tab_label_text (GtkNotebook *notebook,
  *
  * Retrieves the menu label widget of the page containing @child.
  *
- * Return value: (transfer none): the menu label, or %NULL if the
+ * Return value: (transfer none) (allow-none): the menu label, or %NULL if the
  *     notebook page does not have a menu label other than the
  *     default (the tab label).
  **/
@@ -7538,7 +7538,7 @@ gtk_notebook_set_menu_label_text (GtkNotebook *notebook,
  * Retrieves the text of the menu label for the page containing
  *    @child.
  *
- * Return value: the text of the tab label, or %NULL if the
+ * Return value: (allow-none): the text of the tab label, or %NULL if the
  *               widget does not have a menu label other than
  *               the default menu label, or the menu label widget
  *               is not a #GtkLabel. The string is owned by
@@ -8086,7 +8086,7 @@ gtk_notebook_set_tab_detachable (GtkNotebook *notebook,
  *
  * Gets one of the action widgets. See gtk_notebook_set_action_widget().
  *
- * Returns: (transfer none): The action widget with the given @pack_type
+ * Returns: (transfer none) (allow-none): The action widget with the given @pack_type
  *     or %NULL when this action widget has not been set
  *
  * Since: 2.20
diff --git a/gtk/gtkoffscreenwindow.c b/gtk/gtkoffscreenwindow.c
index 0fc1ddc..3087880 100644
--- a/gtk/gtkoffscreenwindow.c
+++ b/gtk/gtkoffscreenwindow.c
@@ -266,7 +266,7 @@ gtk_offscreen_window_new (void)
  * a #GdkPixmap.  If you need to keep this around over window
  * resizes then you should add a reference to it.
  *
- * Returns: (transfer none): A #GdkPixmap pointer to the offscreen pixmap,
+ * Returns: (transfer none) (allow-none): A #GdkPixmap pointer to the offscreen pixmap,
  *     or %NULL.
  *
  * Since: 2.20
@@ -288,7 +288,7 @@ gtk_offscreen_window_get_pixmap (GtkOffscreenWindow *offscreen)
  * and the application should unreference it once it is no longer
  * needed.
  *
- * Returns: (transfer full): A #GdkPixbuf pointer, or %NULL.
+ * Returns: (transfer full) (allow-none): A #GdkPixbuf pointer, or %NULL.
  *
  * Since: 2.20
  */
diff --git a/gtk/gtkpagesetup.c b/gtk/gtkpagesetup.c
index 6f0b448..dc2afa0 100644
--- a/gtk/gtkpagesetup.c
+++ b/gtk/gtkpagesetup.c
@@ -656,7 +656,7 @@ out:
  * @key_file. Returns a new #GtkPageSetup object with the restored
  * page setup, or %NULL if an error occurred.
  *
- * Return value: the restored #GtkPageSetup
+ * Returns: (allow-none): the restored #GtkPageSetup
  *
  * Since: 2.12
  */
diff --git a/gtk/gtkpaned.c b/gtk/gtkpaned.c
index f6225f0..f98b3a6 100644
--- a/gtk/gtkpaned.c
+++ b/gtk/gtkpaned.c
@@ -1540,7 +1540,7 @@ gtk_paned_set_position (GtkPaned *paned,
  * 
  * Obtains the first child of the paned widget.
  * 
- * Return value: (transfer none): first child, or %NULL if it is not set.
+ * Return value: (transfer none) (allow-none): first child, or %NULL if it is not set.
  *
  * Since: 2.4
  **/
@@ -1558,7 +1558,7 @@ gtk_paned_get_child1 (GtkPaned *paned)
  * 
  * Obtains the second child of the paned widget.
  * 
- * Return value: (transfer none): second child, or %NULL if it is not set.
+ * Return value: (transfer none) (allow-none): second child, or %NULL if it is not set.
  *
  * Since: 2.4
  **/
diff --git a/gtk/gtkpapersize.c b/gtk/gtkpapersize.c
index 4576e91..3c846cf 100644
--- a/gtk/gtkpapersize.c
+++ b/gtk/gtkpapersize.c
@@ -798,8 +798,8 @@ gtk_paper_size_get_default_right_margin (GtkPaperSize *size,
  * Reads a paper size from the group @group_name in the key file
  * @key_file. 
  *
- * Returns: a new #GtkPaperSize object with the restored
- *          paper size, or %NULL if an error occurred.
+ * Returns: (allow-none): a new #GtkPaperSize object with the restored
+ *                        paper size, or %NULL if an error occurred.
  *
  * Since: 2.12
  */
diff --git a/gtk/gtkplug.c b/gtk/gtkplug.c
index 99af62a..b73568f 100644
--- a/gtk/gtkplug.c
+++ b/gtk/gtkplug.c
@@ -307,7 +307,7 @@ gtk_plug_get_embedded (GtkPlug *plug)
  *
  * Retrieves the socket the plug is embedded in.
  *
- * Return value: (transfer none): the window of the socket, or %NULL
+ * Return value: (transfer none) (allow-none): the window of the socket, or %NULL
  *
  * Since: 2.14
  **/
diff --git a/gtk/gtkprintoperation.c b/gtk/gtkprintoperation.c
index cf70aa6..1b39a91 100644
--- a/gtk/gtkprintoperation.c
+++ b/gtk/gtkprintoperation.c
@@ -903,7 +903,7 @@ gtk_print_operation_class_init (GtkPrintOperationClass *class)
    * signal is emitted on the operation. Then you can read out any 
    * information you need from the widgets.
    *
-   * Returns: (transfer none): A custom widget that gets embedded in
+   * Returns: (transfer none) (allow-none): A custom widget that gets embedded in
    *          the print dialog, or %NULL
    *
    * Since: 2.10
diff --git a/gtk/gtkprintsettings.c b/gtk/gtkprintsettings.c
index c850dac..6e15ac5 100644
--- a/gtk/gtkprintsettings.c
+++ b/gtk/gtkprintsettings.c
@@ -1717,7 +1717,7 @@ gtk_print_settings_load_file (GtkPrintSettings *settings,
  * file could not be loaded then error is set to either a #GFileError or
  * #GKeyFileError.  See gtk_print_settings_to_file().
  *
- * Return value: the restored #GtkPrintSettings
+ * Returns: (allow-none): the restored #GtkPrintSettings
  * 
  * Since: 2.12
  */
@@ -1810,7 +1810,7 @@ gtk_print_settings_load_key_file (GtkPrintSettings *settings,
  * error occurred. If the file could not be loaded then error is set to either
  * a #GFileError or #GKeyFileError.
  *
- * Return value: the restored #GtkPrintSettings
+ * Returns: (allow-none): the restored #GtkPrintSettings, or %NULL
  *
  * Since: 2.12
  */
diff --git a/gtk/gtkprogressbar.c b/gtk/gtkprogressbar.c
index bd8933d..975c083 100644
--- a/gtk/gtkprogressbar.c
+++ b/gtk/gtkprogressbar.c
@@ -1250,7 +1250,7 @@ gtk_progress_bar_set_orientation (GtkProgressBar           *pbar,
  * to the text, not a copy of it, so will become invalid
  * if you change the text in the progress bar.
  * 
- * Return value: text, or %NULL; this string is owned by the widget
+ * Return value: (allow-none): text, or %NULL; this string is owned by the widget
  * and should not be modified or freed.
  **/
 const gchar*
diff --git a/gtk/gtkrc.c b/gtk/gtkrc.c
index 50b2563..fc74d87 100644
--- a/gtk/gtkrc.c
+++ b/gtk/gtkrc.c
@@ -2065,7 +2065,7 @@ gtk_rc_get_style (GtkWidget *widget)
  *                             G_OBJECT_TYPE (widget));
  * ]|
  * 
- * Return value: (transfer none): A style created by matching with the
+ * Return value: (transfer none) (allow-none): A style created by matching with the
  *     supplied paths, or %NULL if nothing matching was specified and the
  *     default style should be used. The returned value is owned by GTK+
  *     as part of an internal cache, so you must call g_object_ref() on
@@ -3543,7 +3543,7 @@ gtk_rc_find_pixmap_in_path (GtkSettings  *settings,
  * Searches for a theme engine in the GTK+ search path. This function
  * is not useful for applications and should not be used.
  * 
- * Return value: The filename, if found (must be freed with g_free()),
+ * Return value: (allow-none): The filename, if found (must be freed with g_free()),
  *   otherwise %NULL.
  **/
 gchar*
diff --git a/gtk/gtkrecentfilter.c b/gtk/gtkrecentfilter.c
index 9e87998..f236c65 100644
--- a/gtk/gtkrecentfilter.c
+++ b/gtk/gtkrecentfilter.c
@@ -207,7 +207,7 @@ gtk_recent_filter_set_name (GtkRecentFilter *filter,
  * Gets the human-readable name for the filter.
  * See gtk_recent_filter_set_name().
  *
- * Return value: the name of the filter, or %NULL.  The returned string
+ * Return value: (allow-none): the name of the filter, or %NULL.  The returned string
  *   is owned by the filter object and should not be freed.
  *
  * Since: 2.10
diff --git a/gtk/gtkrecentmanager.c b/gtk/gtkrecentmanager.c
index 7bd7572..2feb896 100644
--- a/gtk/gtkrecentmanager.c
+++ b/gtk/gtkrecentmanager.c
@@ -1293,7 +1293,7 @@ build_recent_info (GBookmarkFile  *bookmarks,
  * returns a structure containing informations about the resource
  * like its MIME type, or its display name.
  *
- * Return value: a #GtkRecentInfo structure containing information
+ * Return value: (allow-none): a #GtkRecentInfo structure containing information
  *   about the resource pointed by @uri, or %NULL if the URI was
  *   not registered in the recently used resources list.  Free with
  *   gtk_recent_info_unref().
@@ -2121,7 +2121,7 @@ get_icon_fallback (const gchar *icon_name,
  *
  * Retrieves the icon of size @size associated to the resource MIME type.
  *
- * Return value: (transfer full): a #GdkPixbuf containing the icon,
+ * Return value: (transfer full) (allow-none): a #GdkPixbuf containing the icon,
  *     or %NULL. Use g_object_unref() when finished using the icon.
  *
  * Since: 2.10
@@ -2388,7 +2388,7 @@ gtk_recent_info_get_short_name (GtkRecentInfo *info)
  * is local, it returns a local path; if the resource is not local,
  * it returns the UTF-8 encoded content of gtk_recent_info_get_uri().
  *
- * Return value: a newly allocated UTF-8 string containing the
+ * Return value: (allow-none): a newly allocated UTF-8 string containing the
  *   resource's URI or %NULL. Use g_free() when done using it.
  *
  * Since: 2.10
diff --git a/gtk/gtkscale.c b/gtk/gtkscale.c
index ccf589b..3c12d7b 100644
--- a/gtk/gtkscale.c
+++ b/gtk/gtkscale.c
@@ -1313,7 +1313,7 @@ gtk_scale_finalize (GObject *object)
  * object is owned by the scale so does not need to be freed by
  * the caller.
  *
- * Return value: (transfer none): the #PangoLayout for this scale,
+ * Return value: (transfer none) (allow-none): the #PangoLayout for this scale,
  *     or %NULL if the #GtkScale:draw-value property is %FALSE.
  *
  * Since: 2.4
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index 1704d3c..1e605f2 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -574,7 +574,7 @@ gtk_scrolled_window_get_vadjustment (GtkScrolledWindow *scrolled_window)
  *
  * Returns the horizontal scrollbar of @scrolled_window.
  *
- * Returns: (transfer none): the horizontal scrollbar of the scrolled window,
+ * Returns: (transfer none) (allow-none): the horizontal scrollbar of the scrolled window,
  *     or %NULL if it does not have one.
  *
  * Since: 2.8
@@ -593,7 +593,7 @@ gtk_scrolled_window_get_hscrollbar (GtkScrolledWindow *scrolled_window)
  * 
  * Returns the vertical scrollbar of @scrolled_window.
  *
- * Returns: (transfer none): the vertical scrollbar of the scrolled window,
+ * Returns: (transfer none) (allow-none): the vertical scrollbar of the scrolled window,
  *     or %NULL if it does not have one.
  *
  * Since: 2.8
diff --git a/gtk/gtkselection.c b/gtk/gtkselection.c
index 4d24c81..e00c015 100644
--- a/gtk/gtkselection.c
+++ b/gtk/gtkselection.c
@@ -1547,7 +1547,7 @@ gtk_selection_data_set_text (GtkSelectionData     *selection_data,
  * 
  * Gets the contents of the selection data as a UTF-8 string.
  * 
- * Return value: if the selection data contained a recognized
+ * Return value: (allow-none): if the selection data contained a recognized
  *   text type and it could be converted to UTF-8, a newly allocated
  *   string containing the converted text, otherwise %NULL.
  *   If the result is non-%NULL it must be freed with g_free().
@@ -1665,7 +1665,7 @@ gtk_selection_data_set_pixbuf (GtkSelectionData *selection_data,
  * 
  * Gets the contents of the selection data as a #GdkPixbuf.
  * 
- * Return value: (transfer full): if the selection data contained a recognized
+ * Return value: (transfer full) (allow-none): if the selection data contained a recognized
  *   image type and it could be converted to a #GdkPixbuf, a 
  *   newly allocated pixbuf is returned, otherwise %NULL.
  *   If the result is non-%NULL it must be freed with g_object_unref().
diff --git a/gtk/gtksettings.c b/gtk/gtksettings.c
index 3fbbf00..f9ed87a 100644
--- a/gtk/gtksettings.c
+++ b/gtk/gtksettings.c
@@ -1270,7 +1270,7 @@ gtk_settings_get_for_screen (GdkScreen *screen)
  * Gets the #GtkSettings object for the default GDK screen, creating
  * it if necessary. See gtk_settings_get_for_screen().
  *
- * Return value: (transfer none): a #GtkSettings object. If there is no default
+ * Return value: (transfer none) (allow-none): a #GtkSettings object. If there is no default
  *  screen, then returns %NULL.
  **/
 GtkSettings*
diff --git a/gtk/gtksocket.c b/gtk/gtksocket.c
index e16755a..ab0efda 100644
--- a/gtk/gtksocket.c
+++ b/gtk/gtksocket.c
@@ -378,7 +378,7 @@ gtk_socket_get_id (GtkSocket *socket)
  * Retrieves the window of the plug. Use this to check if the plug has
  * been created inside of the socket.
  *
- * Return value: (transfer none): the window of the plug if available, or %NULL
+ * Return value: (transfer none) (allow-none): the window of the plug if available, or %NULL
  *
  * Since:  2.14
  **/
diff --git a/gtk/gtkstatusicon.c b/gtk/gtkstatusicon.c
index ec89752..c796937 100644
--- a/gtk/gtkstatusicon.c
+++ b/gtk/gtkstatusicon.c
@@ -2058,7 +2058,7 @@ gtk_status_icon_get_storage_type (GtkStatusIcon *status_icon)
  * The caller of this function does not own a reference to the
  * returned pixbuf.
  * 
- * Return value: (transfer none): the displayed pixbuf,
+ * Return value: (transfer none) (allow-none): the displayed pixbuf,
  *     or %NULL if the image is empty.
  *
  * Since: 2.10
@@ -2091,7 +2091,7 @@ gtk_status_icon_get_pixbuf (GtkStatusIcon *status_icon)
  * The returned string is owned by the #GtkStatusIcon and should not
  * be freed or modified.
  * 
- * Return value: stock id of the displayed stock icon,
+ * Return value: (allow-none): stock id of the displayed stock icon,
  *   or %NULL if the image is empty.
  *
  * Since: 2.10
@@ -2124,7 +2124,7 @@ gtk_status_icon_get_stock (GtkStatusIcon *status_icon)
  * The returned string is owned by the #GtkStatusIcon and should not
  * be freed or modified.
  * 
- * Return value: name of the displayed icon, or %NULL if the image is empty.
+ * Return value: (allow-none): name of the displayed icon, or %NULL if the image is empty.
  *
  * Since: 2.10
  **/
@@ -2158,7 +2158,7 @@ gtk_status_icon_get_icon_name (GtkStatusIcon *status_icon)
  *
  * If this function fails, @icon is left unchanged;
  *
- * Returns: (transfer none): the displayed icon, or %NULL if the image is empty
+ * Returns: (transfer none) (allow-none): the displayed icon, or %NULL if the image is empty
  *
  * Since: 2.14
  **/
@@ -2806,7 +2806,7 @@ gtk_status_icon_set_tooltip_text (GtkStatusIcon *status_icon,
  *
  * Gets the contents of the tooltip for @status_icon.
  *
- * Return value: the tooltip text, or %NULL. You should free the
+ * Return value: (allow-none): the tooltip text, or %NULL. You should free the
  *   returned string with g_free() when done.
  *
  * Since: 2.16
@@ -2888,7 +2888,7 @@ gtk_status_icon_set_tooltip_markup (GtkStatusIcon *status_icon,
  *
  * Gets the contents of the tooltip for @status_icon.
  *
- * Return value: the tooltip text, or %NULL. You should free the
+ * Return value: (allow-none): the tooltip text, or %NULL. You should free the
  *   returned string with g_free() when done.
  *
  * Since: 2.16
diff --git a/gtk/gtktestutils.c b/gtk/gtktestutils.c
index d47c2c2..5bbce9e 100644
--- a/gtk/gtktestutils.c
+++ b/gtk/gtktestutils.c
@@ -359,7 +359,7 @@ gtk_test_find_sibling (GtkWidget *base_widget,
  * gtk_test_widget_click() for possible caveats involving the search of
  * such widgets and synthesizing widget events.
  *
- * Returns: (transfer none): a valid widget if any is found or %NULL.
+ * Returns: (transfer none) (allow-none): a valid widget if any is found or %NULL.
  *
  * Since: 2.14
  **/
diff --git a/gtk/gtktextbuffer.c b/gtk/gtktextbuffer.c
index a900915..e5e2341 100644
--- a/gtk/gtktextbuffer.c
+++ b/gtk/gtktextbuffer.c
@@ -2224,7 +2224,7 @@ gtk_text_buffer_delete_mark (GtkTextBuffer *buffer,
  * Returns the mark named @name in buffer @buffer, or %NULL if no such
  * mark exists in the buffer.
  *
- * Return value: (transfer none): a #GtkTextMark, or %NULL
+ * Return value: (transfer none) (allow-none): a #GtkTextMark, or %NULL
  **/
 GtkTextMark*
 gtk_text_buffer_get_mark (GtkTextBuffer *buffer,
diff --git a/gtk/gtktexttagtable.c b/gtk/gtktexttagtable.c
index 1a39eaa..94bc65e 100644
--- a/gtk/gtktexttagtable.c
+++ b/gtk/gtktexttagtable.c
@@ -308,7 +308,7 @@ gtk_text_tag_table_add (GtkTextTagTable *table,
  * 
  * Look up a named tag.
  * 
- * Return value: (transfer none): The tag, or %NULL if none by that name is in the table.
+ * Return value: (transfer none) (allow-none): The tag, or %NULL if none by that name is in the table.
  **/
 GtkTextTag*
 gtk_text_tag_table_lookup (GtkTextTagTable *table,
diff --git a/gtk/gtktextview.c b/gtk/gtktextview.c
index 9ddddec..f89f3a5 100644
--- a/gtk/gtktextview.c
+++ b/gtk/gtktextview.c
@@ -2773,7 +2773,7 @@ gtk_text_view_set_tabs (GtkTextView   *text_view,
  * "standard" (8-space) tabs are used. Free the return value
  * with pango_tab_array_free().
  * 
- * Return value: copy of default tab array, or %NULL if "standard" 
+ * Return value: (allow-none): copy of default tab array, or %NULL if "standard" 
  *    tabs are used; must be freed with pango_tab_array_free().
  **/
 PangoTabArray*
@@ -8379,7 +8379,7 @@ text_window_get_height (GtkTextWindow *win)
  * height is 0, and are nonexistent before the widget has been
  * realized.
  *
- * Return value: (transfer none): a #GdkWindow, or %NULL
+ * Return value: (transfer none) (allow-none): a #GdkWindow, or %NULL
  **/
 GdkWindow*
 gtk_text_view_get_window (GtkTextView *text_view,
diff --git a/gtk/gtktoolbar.c b/gtk/gtktoolbar.c
index b2c4b15..0225d58 100644
--- a/gtk/gtktoolbar.c
+++ b/gtk/gtktoolbar.c
@@ -3000,7 +3000,7 @@ gtk_toolbar_get_n_items (GtkToolbar *toolbar)
  * Returns the @n<!-- -->'th item on @toolbar, or %NULL if the
  * toolbar does not contain an @n<!-- -->'th item.
  *
- * Return value: (transfer none): The @n<!-- -->'th #GtkToolItem on @toolbar,
+ * Return value: (transfer none) (allow-none): The @n<!-- -->'th #GtkToolItem on @toolbar,
  *     or %NULL if there isn't an @n<!-- -->'th item.
  *
  * Since: 2.4
diff --git a/gtk/gtktoolbutton.c b/gtk/gtktoolbutton.c
index e625aef..88d8174 100644
--- a/gtk/gtktoolbutton.c
+++ b/gtk/gtktoolbutton.c
@@ -1005,7 +1005,7 @@ gtk_tool_button_set_label (GtkToolButton *button,
  * doesn't have a label. or uses a the label from a stock item. The returned
  * string is owned by GTK+, and must not be modified or freed.
  * 
- * Return value: The label, or %NULL
+ * Return value: (allow-none): The label, or %NULL
  * 
  * Since: 2.4
  **/
@@ -1156,7 +1156,7 @@ gtk_tool_button_set_icon_name (GtkToolButton *button,
  * Returns the name of the themed icon for the tool button,
  * see gtk_tool_button_set_icon_name().
  *
- * Returns: the icon name or %NULL if the tool button has
+ * Returns: (allow-none): the icon name or %NULL if the tool button has
  * no themed icon
  * 
  * Since: 2.8
@@ -1256,7 +1256,7 @@ gtk_tool_button_set_label_widget (GtkToolButton *button,
  * Returns the widget used as label on @button.
  * See gtk_tool_button_set_label_widget().
  *
- * Return value: (transfer none): The widget used as label
+ * Return value: (transfer none) (allow-none): The widget used as label
  *     on @button, or %NULL.
  *
  * Since: 2.4
@@ -1276,7 +1276,7 @@ gtk_tool_button_get_label_widget (GtkToolButton *button)
  * Return the widget used as icon widget on @button.
  * See gtk_tool_button_set_icon_widget().
  *
- * Return value: (transfer none): The widget used as icon
+ * Return value: (transfer none) (allow-none): The widget used as icon
  *     on @button, or %NULL.
  *
  * Since: 2.4
diff --git a/gtk/gtktoolitemgroup.c b/gtk/gtktoolitemgroup.c
index 3008cba..e0899f7 100644
--- a/gtk/gtktoolitemgroup.c
+++ b/gtk/gtktoolitemgroup.c
@@ -1924,7 +1924,7 @@ gtk_tool_item_group_set_ellipsize (GtkToolItemGroup   *group,
  *
  * Gets the label of @group.
  *
- * Returns: the label of @group. The label is an internal string of @group
+ * Returns: (allow-none): the label of @group. The label is an internal string of @group
  *     and must not be modified. Note that %NULL is returned if a custom
  *     label has been set with gtk_tool_item_group_set_label_widget()
  *
diff --git a/gtk/gtktoolpalette.c b/gtk/gtktoolpalette.c
index b984193..c88de5d 100644
--- a/gtk/gtktoolpalette.c
+++ b/gtk/gtktoolpalette.c
@@ -1541,7 +1541,7 @@ gtk_tool_palette_get_expand (GtkToolPalette   *palette,
  * Gets the item at position (x, y).
  * See gtk_tool_palette_get_drop_group().
  *
- * Returns: (transfer none): the #GtkToolItem at position or %NULL if there is no such item
+ * Returns: (transfer none) (allow-none): the #GtkToolItem at position or %NULL if there is no such item
  *
  * Since: 2.20
  */
@@ -1569,7 +1569,7 @@ gtk_tool_palette_get_drop_item (GtkToolPalette *palette,
  *
  * Gets the group at position (x, y).
  *
- * Returns: (transfer none): the #GtkToolItemGroup at position or %NULL
+ * Returns: (transfer none) (allow-none): the #GtkToolItemGroup at position or %NULL
  *     if there is no such group
  *
  * Since: 2.20
diff --git a/gtk/gtktreemodel.c b/gtk/gtktreemodel.c
index 6328098..0a79dd8 100644
--- a/gtk/gtktreemodel.c
+++ b/gtk/gtktreemodel.c
@@ -406,7 +406,7 @@ gtk_tree_path_new (void)
  * child of that 11th child, and the 1st child of that 5th child.  If an invalid
  * path string is passed in, %NULL is returned.
  *
- * Return value: A newly-created #GtkTreePath, or %NULL
+ * Return value: (allow-none): A newly-created #GtkTreePath, or %NULL
  **/
 GtkTreePath *
 gtk_tree_path_new_from_string (const gchar *path)
@@ -609,7 +609,7 @@ gtk_tree_path_get_depth (GtkTreePath *path)
  * Returns the current indices of @path.  This is an array of integers, each
  * representing a node in a tree.  This value should not be freed.
  *
- * Return value: The current indices, or %NULL.
+ * Return value: (allow-none): The current indices, or %NULL.
  **/
 gint *
 gtk_tree_path_get_indices (GtkTreePath *path)
@@ -1913,7 +1913,7 @@ gtk_tree_row_reference_unref_path (GtkTreePath  *path,
  * signals emitted by @model, and updates its path appropriately.  If @path
  * isn't a valid path in @model, then %NULL is returned.
  * 
- * Return value: A newly allocated #GtkTreeRowReference, or %NULL
+ * Return value: (allow-none): A newly allocated #GtkTreeRowReference, or %NULL
  **/
 GtkTreeRowReference *
 gtk_tree_row_reference_new (GtkTreeModel *model,
@@ -1956,7 +1956,7 @@ gtk_tree_row_reference_new (GtkTreeModel *model,
  * carefully monitor exactly when a row reference updates itself, and is not
  * generally needed by most applications.
  *
- * Return value: A newly allocated #GtkTreeRowReference, or %NULL
+ * Return value: (allow-none): A newly allocated #GtkTreeRowReference, or %NULL
  **/
 GtkTreeRowReference *
 gtk_tree_row_reference_new_proxy (GObject      *proxy,
@@ -2022,7 +2022,7 @@ gtk_tree_row_reference_new_proxy (GObject      *proxy,
  * Returns a path that the row reference currently points to, or %NULL if the
  * path pointed to is no longer valid.
  * 
- * Return value: A current path, or %NULL.
+ * Return value: (allow-none): A current path, or %NULL.
  **/
 GtkTreePath *
 gtk_tree_row_reference_get_path (GtkTreeRowReference *reference)
diff --git a/gtk/gtktreemodelfilter.c b/gtk/gtktreemodelfilter.c
index 3adc82d..479e64f 100644
--- a/gtk/gtktreemodelfilter.c
+++ b/gtk/gtktreemodelfilter.c
@@ -3336,7 +3336,7 @@ gtk_real_tree_model_filter_convert_child_path_to_path (GtkTreeModelFilter *filte
  * child model or points to a row which is not visible in @filter, then %NULL
  * is returned.
  *
- * Return value: A newly allocated #GtkTreePath, or %NULL.
+ * Return value: (allow-none): A newly allocated #GtkTreePath, or %NULL.
  *
  * Since: 2.4
  */
@@ -3379,7 +3379,7 @@ gtk_tree_model_filter_convert_child_path_to_path (GtkTreeModelFilter *filter,
  * point to the same location in the model not being filtered. If @filter_path
  * does not point to a location in the child model, %NULL is returned.
  *
- * Return value: A newly allocated #GtkTreePath, or %NULL.
+ * Return value: (allow-none): A newly allocated #GtkTreePath, or %NULL.
  *
  * Since: 2.4
  */
diff --git a/gtk/gtktreemodelsort.c b/gtk/gtktreemodelsort.c
index 4d085f4..4f798d3 100644
--- a/gtk/gtktreemodelsort.c
+++ b/gtk/gtktreemodelsort.c
@@ -2071,7 +2071,7 @@ gtk_real_tree_model_sort_convert_child_path_to_path (GtkTreeModelSort *tree_mode
  * point to the same row in the sorted model.  If @child_path isn't a valid 
  * path on the child model, then %NULL is returned.
  * 
- * Return value: A newly allocated #GtkTreePath, or %NULL
+ * Return value: (allow-none): A newly allocated #GtkTreePath, or %NULL
  **/
 GtkTreePath *
 gtk_tree_model_sort_convert_child_path_to_path (GtkTreeModelSort *tree_model_sort,
@@ -2143,7 +2143,7 @@ gtk_tree_model_sort_convert_child_iter_to_iter (GtkTreeModelSort *tree_model_sor
  * sorted.  If @sorted_path does not point to a location in the child model, 
  * %NULL is returned.
  * 
- * Return value: A newly allocated #GtkTreePath, or %NULL
+ * Return value: (allow-none): A newly allocated #GtkTreePath, or %NULL
  **/
 GtkTreePath *
 gtk_tree_model_sort_convert_path_to_child_path (GtkTreeModelSort *tree_model_sort,
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index 89301eb..f6680af 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -10717,7 +10717,7 @@ gtk_tree_view_new_with_model (GtkTreeModel *model)
  * Returns the model the #GtkTreeView is based on.  Returns %NULL if the
  * model is unset.
  *
- * Return value: (transfer none): A #GtkTreeModel, or %NULL if none is currently being used.
+ * Return value: (transfer none) (allow-none): A #GtkTreeModel, or %NULL if none is currently being used.
  **/
 GtkTreeModel *
 gtk_tree_view_get_model (GtkTreeView *tree_view)
@@ -10904,7 +10904,7 @@ gtk_tree_view_get_selection (GtkTreeView *tree_view)
  *
  * Gets the #GtkAdjustment currently being used for the horizontal aspect.
  *
- * Return value: (transfer none): A #GtkAdjustment object, or %NULL
+ * Return value: (transfer none) (allow-none): A #GtkAdjustment object, or %NULL
  *     if none is currently being used.
  **/
 GtkAdjustment *
@@ -10944,7 +10944,7 @@ gtk_tree_view_set_hadjustment (GtkTreeView   *tree_view,
  *
  * Gets the #GtkAdjustment currently being used for the vertical aspect.
  *
- * Return value: (transfer none): A #GtkAdjustment object, or %NULL
+ * Return value: (transfer none) (allow-none): A #GtkAdjustment object, or %NULL
  *     if none is currently being used.
  **/
 GtkAdjustment *
@@ -11448,7 +11448,7 @@ gtk_tree_view_insert_column_with_data_func  (GtkTreeView               *tree_vie
  *
  * Gets the #GtkTreeViewColumn at the given position in the #tree_view.
  *
- * Return value: (transfer none): The #GtkTreeViewColumn, or %NULL if the
+ * Return value: (transfer none) (allow-none): The #GtkTreeViewColumn, or %NULL if the
  *     position is outside the range of columns.
  **/
 GtkTreeViewColumn *
@@ -12774,7 +12774,7 @@ gtk_tree_view_set_cursor_on_cell (GtkTreeView       *tree_view,
  * This is used primarily to compare to <literal>event->window</literal>
  * to confirm that the event on @tree_view is on the right window.
  *
- * Return value: (transfer none): A #GdkWindow, or %NULL when @tree_view
+ * Return value: (transfer none) (allow-none): A #GdkWindow, or %NULL when @tree_view
  *     hasn't been realized yet
  **/
 GdkWindow *
@@ -14089,7 +14089,7 @@ gtk_tree_view_set_search_equal_func (GtkTreeView                *tree_view,
  * entry for @tree_view.  In case the built-in entry is being used, %NULL
  * will be returned.
  *
- * Return value: (transfer none): the entry currently in use as search entry.
+ * Return value: (transfer none) (allow-none): the entry currently in use as search entry, or %NULL.
  *
  * Since: 2.10
  */
diff --git a/gtk/gtktreeviewcolumn.c b/gtk/gtktreeviewcolumn.c
index 03dbdaa..da5b2a9 100644
--- a/gtk/gtktreeviewcolumn.c
+++ b/gtk/gtktreeviewcolumn.c
@@ -2275,7 +2275,7 @@ gtk_tree_view_column_set_widget (GtkTreeViewColumn *tree_column,
  * Returns the #GtkWidget in the button on the column header.
  * If a custom widget has not been set then %NULL is returned.
  *
- * Return value: (transfer none): The #GtkWidget in the column
+ * Return value: (transfer none) (allow-none): The #GtkWidget in the column
  *     header, or %NULL
  **/
 GtkWidget *
@@ -3772,7 +3772,7 @@ gtk_tree_view_column_queue_resize (GtkTreeViewColumn *tree_column)
  * If @column is currently not inserted in any tree view, %NULL is
  * returned.
  *
- * Return value: (transfer none): The tree view wherein @column has
+ * Return value: (transfer none) (allow-none): The tree view wherein @column has
  *     been inserted if any, %NULL otherwise.
  *
  * Since: 2.12
diff --git a/gtk/gtkuimanager.c b/gtk/gtkuimanager.c
index d004cf1..58a9acb 100644
--- a/gtk/gtkuimanager.c
+++ b/gtk/gtkuimanager.c
@@ -837,7 +837,7 @@ gtk_ui_manager_get_accel_group (GtkUIManager *self)
  * function to some container or explicitly ref them, they will survive the
  * destruction of the ui manager.
  *
- * Return value: (transfer none): the widget found by following the path, or %NULL if no widget
+ * Return value: (transfer none) (allow-none): the widget found by following the path, or %NULL if no widget
  *   was found.
  *
  * Since: 2.4
@@ -929,7 +929,7 @@ gtk_ui_manager_get_toplevels (GtkUIManager         *self,
  * Looks up an action by following a path. See gtk_ui_manager_get_widget()
  * for more information about paths.
  * 
- * Return value: (transfer none): the action whose proxy widget is found by following the path, 
+ * Return value: (transfer none) (allow-none): the action whose proxy widget is found by following the path, 
  *     or %NULL if no widget was found.
  *
  * Since: 2.4
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 1d1f6bb..a25fa90 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -4159,7 +4159,7 @@ gtk_widget_size_allocate (GtkWidget	*widget,
  * Find the common ancestor of @widget_a and @widget_b that
  * is closest to the two widgets.
  * 
- * Return value: the closest common ancestor of @widget_a and
+ * Return value: (allow-none): the closest common ancestor of @widget_a and
  *   @widget_b or %NULL if @widget_a and @widget_b do not
  *   share a common ancestor.
  **/
@@ -6468,7 +6468,7 @@ gtk_widget_set_parent (GtkWidget *widget,
  *
  * Returns the parent container of @widget.
  *
- * Return value: (transfer none): the parent container of @widget, or %NULL
+ * Return value: (transfer none) (allow-none): the parent container of @widget, or %NULL
  **/
 GtkWidget *
 gtk_widget_get_parent (GtkWidget *widget)
@@ -7415,7 +7415,7 @@ gtk_widget_create_pango_layout (GtkWidget   *widget,
  * the application and should not be modified. The pixbuf should be freed
  * after use with g_object_unref().
  *
- * Return value: (transfer full): a new pixbuf, or %NULL if the
+ * Return value: (transfer full) (allow-none): a new pixbuf, or %NULL if the
  *     stock ID wasn't known
  **/
 GdkPixbuf*
@@ -8254,7 +8254,7 @@ gtk_widget_get_toplevel (GtkWidget *widget)
  * Note that unlike gtk_widget_is_ancestor(), gtk_widget_get_ancestor() 
  * considers @widget to be an ancestor of itself.
  *
- * Return value: (transfer none): the ancestor widget, or %NULL if not found
+ * Return value: (transfer none) (allow-none): the ancestor widget, or %NULL if not found
  **/
 GtkWidget*
 gtk_widget_get_ancestor (GtkWidget *widget,
@@ -8506,7 +8506,7 @@ gtk_widget_set_composite_name (GtkWidget   *widget,
  *
  * Obtains the composite name of a widget. 
  *
- * Returns: the composite name of @widget, or %NULL if @widget is not
+ * Returns: (allow-none): the composite name of @widget, or %NULL if @widget is not
  *   a composite child. The string should be freed when it is no 
  *   longer needed.
  **/
@@ -8965,7 +8965,7 @@ gtk_widget_real_size_request (GtkWidget         *widget,
  * 
  * Returns colormap currently pushed by gtk_widget_push_colormap, if any.
  * 
- * Return value: the currently pushed colormap, or %NULL if there is none.
+ * Return value: (allow-none): the currently pushed colormap, or %NULL if there is none.
  **/
 GdkColormap*
 _gtk_widget_peek_colormap (void)
@@ -9002,7 +9002,7 @@ _gtk_widget_set_pointer_window (GtkWidget *widget,
  * _gtk_widget_get_pointer_window:
  * @widget: a #GtkWidget.
  *
- * Return value: the pointer window set on the #GdkScreen @widget is attached
+ * Return value: (allow-none): the pointer window set on the #GdkScreen @widget is attached
  * to, or %NULL.
  */
 GdkWindow *
@@ -9345,7 +9345,7 @@ gtk_widget_propagate_state (GtkWidget           *widget,
  * 
  * Get the #GtkWidgetAuxInfo structure for the widget.
  * 
- * Return value: the #GtkAuxInfo structure for the widget, or
+ * Return value: (allow-none): the #GtkAuxInfo structure for the widget, or
  *    %NULL if @create is %FALSE and one doesn't already exist.
  */
 GtkWidgetAuxInfo*
@@ -11162,7 +11162,7 @@ gtk_widget_set_tooltip_text (GtkWidget   *widget,
  *
  * Gets the contents of the tooltip for @widget.
  *
- * Return value: the tooltip text, or %NULL. You should free the
+ * Return value: (allow-none): the tooltip text, or %NULL. You should free the
  *   returned string with g_free() when done.
  *
  * Since: 2.12
@@ -11210,7 +11210,7 @@ gtk_widget_set_tooltip_markup (GtkWidget   *widget,
  *
  * Gets the contents of the tooltip for @widget.
  *
- * Return value: the tooltip text, or %NULL. You should free the
+ * Return value: (allow-none): the tooltip text, or %NULL. You should free the
  *   returned string with g_free() when done.
  *
  * Since: 2.12
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 4de3215..ba76121 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -1427,7 +1427,7 @@ gtk_window_set_title (GtkWindow   *window,
  *
  * Retrieves the title of the window. See gtk_window_set_title().
  *
- * Return value: the title of the window, or %NULL if none has
+ * Return value: (allow-none): the title of the window, or %NULL if none has
  *    been set explicitely. The returned string is owned by the widget
  *    and must not be modified or freed.
  **/
@@ -1576,7 +1576,7 @@ gtk_window_set_startup_id (GtkWindow   *window,
  * Returns the role of the window. See gtk_window_set_role() for
  * further explanation.
  *
- * Return value: the role of the window if set, or %NULL. The
+ * Return value: (allow-none): the role of the window if set, or %NULL. The
  *   returned is owned by the widget and must not be modified
  *   or freed.
  **/
@@ -1711,7 +1711,7 @@ gtk_window_set_default (GtkWindow *window,
  * Returns the default widget for @window. See gtk_window_set_default()
  * for more details.
  *
- * Returns: (transfer none): the default widget, or %NULL if there is none.
+ * Returns: (transfer none) (allow-none): the default widget, or %NULL if there is none.
  *
  * Since: 2.14
  **/
@@ -2002,7 +2002,7 @@ gtk_window_activate_focus (GtkWindow *window)
  * is not focused then  <literal>gtk_widget_has_focus (widget)</literal> will
  * not be %TRUE for the widget.
  *
- * Return value: (transfer none): the currently focused widget, or %NULL if there is none.
+ * Return value: (transfer none) (allow-none): the currently focused widget, or %NULL if there is none.
  **/
 GtkWidget *
 gtk_window_get_focus (GtkWindow *window)
@@ -2363,7 +2363,7 @@ gtk_window_set_transient_for  (GtkWindow *window,
  * Fetches the transient parent for this window. See
  * gtk_window_set_transient_for().
  *
- * Return value: (transfer none): the transient parent for this window, or %NULL
+ * Return value: (transfer none) (allow-none): the transient parent for this window, or %NULL
  *    if no transient parent has been set.
  **/
 GtkWindow *
@@ -3578,7 +3578,7 @@ gtk_window_set_icon_name (GtkWindow   *window,
  * Returns the name of the themed icon for the window,
  * see gtk_window_set_icon_name().
  *
- * Returns: the icon name or %NULL if the window has 
+ * Returns: (allow-none): the icon name or %NULL if the window has 
  * no themed icon
  *
  * Since: 2.6
@@ -7745,7 +7745,7 @@ gtk_window_group_list_windows (GtkWindowGroup *window_group)
  * @window is %NULL or if @window does not have an explicit
  * window group.
  *
- * Returns: (transfer none): the #GtkWindowGroup for a window or the default group
+ * Returns: (transfer none) (allow-none): the #GtkWindowGroup for a window or the default group, or %NULL
  *
  * Since: 2.10
  */
