diff --git a/app/core/gimp-utils.c b/app/core/gimp-utils.c
index 3cc9d34f4a..824cfd8307 100644
--- a/app/core/gimp-utils.c
+++ b/app/core/gimp-utils.c
@@ -784,8 +784,8 @@ gimp_file_with_new_extension (GFile *file,
  * Such function unfortunately does not exist in glib, which only allows
  * to delete single files or empty directories by default.
  *
- * Returns: #TRUE if @file was successfully deleted and all its
- * children, #FALSE otherwise with @error filled.
+ * Returns: %TRUE if @file was successfully deleted and all its
+ * children, %FALSE otherwise with @error filled.
  */
 gboolean
 gimp_file_delete_recursive (GFile   *file,
diff --git a/app/core/gimpimage-arrange.c b/app/core/gimpimage-arrange.c
index 6b6b05ee82..e1174fb365 100644
--- a/app/core/gimpimage-arrange.c
+++ b/app/core/gimpimage-arrange.c
@@ -48,7 +48,7 @@ static gint    offset_compare  (gconstpointer      a,
  * @image:                The #GimpImage to which the objects belong.
  * @list:                 A #GList of objects to be aligned.
  * @alignment:            The point on each target object to bring into alignment.
- * @reference:            The #GObject to align the targets with, or #NULL.
+ * @reference:            The #GObject to align the targets with, or %NULL.
  * @reference_alignment:  The point on the reference object to align the target item with..
  * @offset:               How much to shift the target from perfect alignment..
  *
@@ -61,7 +61,7 @@ static gint    offset_compare  (gconstpointer      a,
  *
  * The objects in the list are sorted into increasing order before
  * being arranged, where the order is defined by the type of alignment
- * being requested.  If the @reference argument is #NULL, then the
+ * being requested.  If the @reference argument is %NULL, then the
  * first object in the sorted list is used as reference.
  *
  * When there are multiple target objects, they are arranged so that
diff --git a/app/core/gimpitem.c b/app/core/gimpitem.c
index 1cc0992ad8..03283b383e 100644
--- a/app/core/gimpitem.c
+++ b/app/core/gimpitem.c
@@ -741,7 +741,7 @@ gimp_item_new (GType        type,
  * gimp_item_remove:
  * @item: the #GimpItem to remove.
  *
- * This function sets the 'removed' flag on @item to #TRUE, and emits
+ * This function sets the 'removed' flag on @item to %TRUE, and emits
  * a 'removed' signal on the item.
  */
 void
@@ -1245,7 +1245,7 @@ gimp_item_end_transform (GimpItem *item,
  * @item:      The #GimpItem to move.
  * @offset_x:  Increment to the X offset of the item.
  * @offset_y:  Increment to the Y offset of the item.
- * @push_undo: If #TRUE, create an entry in the image's undo stack
+ * @push_undo: If %TRUE, create an entry in the image's undo stack
  *             for this action.
  *
  * Adds the specified increments to the X and Y offsets for the item.
@@ -1289,8 +1289,8 @@ gimp_item_translate (GimpItem *item,
  *
  * Scales item dimensions, then snaps them to pixel centers
  *
- * Returns: #FALSE if any dimension reduces to zero as a result
- *          of this; otherwise, returns #TRUE.
+ * Returns: %FALSE if any dimension reduces to zero as a result
+ *          of this; otherwise, returns %TRUE.
  **/
 gboolean
 gimp_item_check_scaling (GimpItem *item,
@@ -1386,9 +1386,9 @@ gimp_item_scale (GimpItem              *item,
  * set of items. In this context, the item's dimensions and offsets
  * from the sides of the containing image all change by these
  * predetermined factors. By fiat, the fixed point of the transform is
- * the upper left hand corner of the image. Returns #FALSE if a
+ * the upper left hand corner of the image. Returns %FALSE if a
  * requested scale factor is zero or if a scaling zero's out a item
- * dimension; returns #TRUE otherwise.
+ * dimension; returns %TRUE otherwise.
  *
  * Use gimp_item_scale() in circumstances where new item width
  * and height dimensions are predetermined instead.
@@ -1396,8 +1396,8 @@ gimp_item_scale (GimpItem              *item,
  * Side effects: Undo set created for item. Old item imagery
  *               scaled & painted to new item tiles.
  *
- * Returns: #TRUE, if the scaled item has positive dimensions
- *          #FALSE if the scaled item has at least one zero dimension
+ * Returns: %TRUE, if the scaled item has positive dimensions
+ *          %FALSE if the scaled item has at least one zero dimension
  **/
 gboolean
 gimp_item_scale_by_factors (GimpItem              *item,
@@ -1427,8 +1427,8 @@ gimp_item_scale_by_factors (GimpItem              *item,
  * Same as gimp_item_scale_by_factors(), but with the option to specify
  * custom input and output points of origin for the transformation.
  *
- * Returns: #TRUE, if the scaled item has positive dimensions
- *          #FALSE if the scaled item has at least one zero dimension
+ * Returns: %TRUE, if the scaled item has positive dimensions
+ *          %FALSE if the scaled item has at least one zero dimension
  **/
 gboolean
 gimp_item_scale_by_factors_with_origin (GimpItem              *item,
@@ -1493,7 +1493,7 @@ gimp_item_scale_by_factors_with_origin (GimpItem              *item,
  * Sets item dimensions to new_width and
  * new_height. Derives vertical and horizontal scaling
  * transforms from new width and height. If local_origin is
- * #TRUE, the fixed point of the scaling transform coincides
+ * %TRUE, the fixed point of the scaling transform coincides
  * with the item's center point.  Otherwise, the fixed
  * point is taken to be [-GimpItem::offset_x, -GimpItem::->offset_y].
  *
diff --git a/app/core/gimplineart.c b/app/core/gimplineart.c
index 93448e47e0..78ee26904c 100644
--- a/app/core/gimplineart.c
+++ b/app/core/gimplineart.c
@@ -881,7 +881,7 @@ gimp_line_art_input_invalidate_preview (GimpViewable *viewable,
  * https://hal.archives-ouvertes.fr/hal-01891876
  *
  * Returns: a new #GeglBuffer of format "Y u8" representing the
- *          binarized @line_art. If @lineart_distmap is not #NULL, a
+ *          binarized @line_art. If @lineart_distmap is not %NULL, a
  *          newly allocated float buffer is returned, which can be used
  *          for overflowing created masks later.
  */
@@ -2065,7 +2065,7 @@ gimp_number_of_transitions (GArray     *pixels,
  * micro-area will be added to @fill_pixels to be later filled along
  * with the candidate pixels.
  *
- * Returns: #TRUE if @pixels should be added to @mask, #FALSE otherwise.
+ * Returns: %TRUE if @pixels should be added to @mask, %FALSE otherwise.
  */
 static gboolean
 gimp_line_art_allow_closure (GeglBuffer *mask,
diff --git a/app/core/gimptag.c b/app/core/gimptag.c
index 95c4954260..063b908a7c 100644
--- a/app/core/gimptag.c
+++ b/app/core/gimptag.c
@@ -411,7 +411,7 @@ gimp_tag_is_tag_separator (gunichar c)
  * gimp_tag_or_null_ref:
  * @tag: a #GimpTag
  *
- * A simple wrapper around g_object_ref() that silently accepts #NULL.
+ * A simple wrapper around g_object_ref() that silently accepts %NULL.
  **/
 void
 gimp_tag_or_null_ref (GimpTag *tag_or_null)
@@ -428,7 +428,7 @@ gimp_tag_or_null_ref (GimpTag *tag_or_null)
  * gimp_tag_or_null_unref:
  * @tag: a #GimpTag
  *
- * A simple wrapper around g_object_unref() that silently accepts #NULL.
+ * A simple wrapper around g_object_unref() that silently accepts %NULL.
  **/
 void
 gimp_tag_or_null_unref (GimpTag *tag_or_null)
diff --git a/app/core/gimptagged.c b/app/core/gimptagged.c
index 7875f9afdb..4006f0960c 100644
--- a/app/core/gimptagged.c
+++ b/app/core/gimptagged.c
@@ -219,10 +219,10 @@ gimp_tagged_get_identifier (GimpTagged *tagged)
  * example if the user has renamed a data file since the last session.
  *
  * If the object does not want to support such remapping (objects not
- * stored in file for example) it can return #NULL.
+ * stored in file for example) it can return %NULL.
  *
  * Return value: checksum string if object needs identifier remapping,
- * #NULL otherwise. Returned string must be freed with #g_free().
+ * %NULL otherwise. Returned string must be freed with #g_free().
  **/
 gchar *
 gimp_tagged_get_checksum (GimpTagged *tagged)
@@ -237,7 +237,7 @@ gimp_tagged_get_checksum (GimpTagged *tagged)
  * @tagged: an object that implements the %GimpTagged interface
  * @tag:    a %GimpTag
  *
- * Return value: #TRUE if the object has @tag, #FALSE otherwise.
+ * Return value: %TRUE if the object has @tag, %FALSE otherwise.
  **/
 gboolean
 gimp_tagged_has_tag (GimpTagged *tagged,
diff --git a/app/core/gimpviewable.c b/app/core/gimpviewable.c
index 1f031672db..5c6e3f4a7d 100644
--- a/app/core/gimpviewable.c
+++ b/app/core/gimpviewable.c
@@ -630,12 +630,12 @@ gimp_viewable_expanded_changed (GimpViewable *viewable)
  * @aspect_height:  unscaled height of the preview for an item.
  * @width:          maximum available width for scaled preview.
  * @height:         maximum available height for scaled preview.
- * @dot_for_dot:    if #TRUE, ignore any differences in axis resolution.
+ * @dot_for_dot:    if %TRUE, ignore any differences in axis resolution.
  * @xresolution:    resolution in the horizontal direction.
  * @yresolution:    resolution in the vertical direction.
  * @return_width:   place to return the calculated preview width.
  * @return_height:  place to return the calculated preview height.
- * @scaling_up:     returns #TRUE here if the calculated preview size
+ * @scaling_up:     returns %TRUE here if the calculated preview size
  *                  is larger than the viewable itself.
  *
  * A utility function, for calculating the dimensions of a preview
@@ -646,7 +646,7 @@ gimp_viewable_expanded_changed (GimpViewable *viewable)
  * preview is scaled to be as large as possible without exceeding
  * these constraints.
  *
- * If @dot_for_dot is #TRUE, and @xresolution and @yresolution are
+ * If @dot_for_dot is %TRUE, and @xresolution and @yresolution are
  * different, then these results are corrected for the difference in
  * resolution on the two axes, so that the requested aspect ratio
  * applies to the appearance of the display rather than to pixel
@@ -720,7 +720,7 @@ gimp_viewable_get_size (GimpViewable  *viewable,
  * @viewable:    the object for which to calculate the preview size.
  * @size:        requested size for preview.
  * @popup:       %TRUE if the preview is intended for a popup window.
- * @dot_for_dot: If #TRUE, ignore any differences in X and Y resolution.
+ * @dot_for_dot: If %TRUE, ignore any differences in X and Y resolution.
  * @width:       return location for the the calculated width.
  * @height:      return location for the calculated height.
  *
@@ -760,7 +760,7 @@ gimp_viewable_get_preview_size (GimpViewable *viewable,
  * @viewable:     the object for which to calculate the popup size.
  * @width:        the width of the preview from which the popup will be shown.
  * @height:       the height of the preview from which the popup will be shown.
- * @dot_for_dot:  If #TRUE, ignore any differences in X and Y resolution.
+ * @dot_for_dot:  If %TRUE, ignore any differences in X and Y resolution.
  * @popup_width:  return location for the calculated popup width.
  * @popup_height: return location for the calculated popup height.
  *
@@ -842,14 +842,14 @@ gimp_viewable_get_popup_size (GimpViewable *viewable,
  * Gets a preview for a viewable object, by running through a variety
  * of methods until it finds one that works.  First, if an
  * implementation exists of a "get_preview" method, it is tried, and
- * the result is returned if it is not #NULL.  Second, the function
+ * the result is returned if it is not %NULL.  Second, the function
  * checks to see whether there is a cached preview with the correct
  * dimensions; if so, it is returned.  If neither of these works, then
  * the function looks for an implementation of the "get_new_preview"
  * method, and executes it, caching the result.  If everything fails,
- * #NULL is returned.
+ * %NULL is returned.
  *
- * Returns: A #GimpTempBuf containing the preview image, or #NULL if
+ * Returns: A #GimpTempBuf containing the preview image, or %NULL if
  *          none can be found or created.
  **/
 GimpTempBuf *
@@ -912,7 +912,7 @@ gimp_viewable_get_preview (GimpViewable *viewable,
  * then if that fails for a "get_preview" method.  This function does
  * not look for a cached preview.
  *
- * Returns: A #GimpTempBuf containing the preview image, or #NULL if
+ * Returns: A #GimpTempBuf containing the preview image, or %NULL if
  *          none can be found or created.
  **/
 GimpTempBuf *
@@ -999,14 +999,14 @@ gimp_viewable_get_dummy_preview (GimpViewable *viewable,
  * Gets a preview for a viewable object, by running through a variety
  * of methods until it finds one that works.  First, if an
  * implementation exists of a "get_pixbuf" method, it is tried, and
- * the result is returned if it is not #NULL.  Second, the function
+ * the result is returned if it is not %NULL.  Second, the function
  * checks to see whether there is a cached preview with the correct
  * dimensions; if so, it is returned.  If neither of these works, then
  * the function looks for an implementation of the "get_new_pixbuf"
  * method, and executes it, caching the result.  If everything fails,
- * #NULL is returned.
+ * %NULL is returned.
  *
- * Returns: A #GdkPixbuf containing the preview pixbuf, or #NULL if none can
+ * Returns: A #GdkPixbuf containing the preview pixbuf, or %NULL if none can
  *          be found or created.
  **/
 GdkPixbuf *
@@ -1069,7 +1069,7 @@ gimp_viewable_get_pixbuf (GimpViewable *viewable,
  * then if that fails for a "get_pixbuf" method.  This function does
  * not look for a cached pixbuf.
  *
- * Returns: A #GdkPixbuf containing the preview, or #NULL if none can
+ * Returns: A #GdkPixbuf containing the preview, or %NULL if none can
  *          be created.
  **/
 GdkPixbuf *
diff --git a/app/display/gimpdisplayshell.c b/app/display/gimpdisplayshell.c
index c567475289..9beed2df36 100644
--- a/app/display/gimpdisplayshell.c
+++ b/app/display/gimpdisplayshell.c
@@ -1851,7 +1851,7 @@ gimp_display_shell_set_highlight (GimpDisplayShell   *shell,
  * @shell: a #GimpDisplayShell
  * @mask:  a #GimpDrawable (1 byte per pixel)
  * @color: the color to use for drawing the mask
- * @inverted: #TRUE if the mask should be drawn inverted
+ * @inverted: %TRUE if the mask should be drawn inverted
  *
  * Previews a mask originating at offset_x, offset_x. Depending on
  * @inverted, pixels that are selected or not selected are tinted with
diff --git a/app/widgets/gimpdialogfactory.c b/app/widgets/gimpdialogfactory.c
index b1d5cc8c3a..fb5f22eabe 100644
--- a/app/widgets/gimpdialogfactory.c
+++ b/app/widgets/gimpdialogfactory.c
@@ -772,7 +772,7 @@ gimp_dialog_factory_add_session_info (GimpDialogFactory *factory,
  * @factory:      a #GimpDialogFactory
  * @monitor:      the #GdkMonitor the dialog should appear on
  * @parent:       the #GtkWidget from which the raised dialog
- *                originated, if applicable, #NULL otherwise.
+ *                originated, if applicable, %NULL otherwise.
  * @identifiers:  a '|' separated list of identifiers of dialogs as
  *                registered with gimp_dialog_factory_register_entry()
  * @view_size:    the initial preview size if a dialog needs to be created
diff --git a/app/widgets/gimplanguagecombobox.c b/app/widgets/gimplanguagecombobox.c
index 428277408e..924b0196ec 100644
--- a/app/widgets/gimplanguagecombobox.c
+++ b/app/widgets/gimplanguagecombobox.c
@@ -70,10 +70,10 @@ gimp_language_combo_box_init (GimpLanguageComboBox *combo)
  * @empty_label: the label for empty language code.
  *
  * Returns a combo box containing all GUI localization languages if
- * @manual_l18n is #FALSE, or all manual localization languages
- * otherwise. If @empty_label is not #NULL, an entry with this label
+ * @manual_l18n is %FALSE, or all manual localization languages
+ * otherwise. If @empty_label is not %NULL, an entry with this label
  * will be created for the language code "", otherwise if @empty_label
- * is #NULL and @manual_l18n is #FALSE, the entry will be "System
+ * is %NULL and @manual_l18n is %FALSE, the entry will be "System
  * Language" localized in itself (not in the GUI language).
  */
 GtkWidget *
diff --git a/app/widgets/gimppropwidgets.c b/app/widgets/gimppropwidgets.c
index 45da929148..6e6e012eee 100644
--- a/app/widgets/gimppropwidgets.c
+++ b/app/widgets/gimppropwidgets.c
@@ -91,12 +91,12 @@ static void         connect_notify     (GObject     *config,
  * @button_label:  Toggle widget title appearing as a frame title.
  * @child:         Child #GtkWidget of the returned frame.
  * @button:        Pointer to the #GtkCheckButton used as frame title
- *                 if not #NULL.
+ *                 if not %NULL.
  *
  * Creates a #GimpFrame containing @child, using a #GtkCheckButton as a
  * title whose value is tied to the boolean @property_name.
- * @child will be visible when @property_name is #TRUE, hidden otherwise.
- * If @button_label is #NULL, the @property_name's nick will be used as
+ * @child will be visible when @property_name is %TRUE, hidden otherwise.
+ * If @button_label is %NULL, the @property_name's nick will be used as
  * label of the #GtkCheckButton title.
  *
  * Return value:  A new #GimpFrame widget.
@@ -342,7 +342,7 @@ static void   gimp_prop_color_button_notify   (GObject    *config,
  *
  * Creates a #GimpColorPanel to set and display the value of a #GimpRGB
  * property.  Pressing the button brings up a color selector dialog.
- * If @title is #NULL, the @property_name's nick will be used as label
+ * If @title is %NULL, the @property_name's nick will be used as label
  * of the returned widget.
  *
  * Return value:  A new #GimpColorPanel widget.
@@ -461,7 +461,7 @@ static void   gimp_prop_adjustment_notify   (GObject       *config,
  *
  * Creates a #GimpSpinScale to set and display the value of a
  * gdouble property in a very space-efficient way.
- * If @label is #NULL, the @property_name's nick will be used as label
+ * If @label is %NULL, the @property_name's nick will be used as label
  * of the returned widget.
  * The property's lower and upper values will be used as min/max of the
  * #GimpSpinScale.
diff --git a/libgimp/gimp.c b/libgimp/gimp.c
index a521e89981..09a446a9fd 100644
--- a/libgimp/gimp.c
+++ b/libgimp/gimp.c
@@ -1035,7 +1035,7 @@ gimp_export_color_profile (void)
  * gimp_export_exif:
  *
  * Returns whether file plug-ins should default to exporting Exif
- * metadata, according preferences (original settings is #FALSE since
+ * metadata, according preferences (original settings is %FALSE since
  * metadata can contain sensitive information).
  *
  * Return value: TRUE if preferences are set to export Exif.
@@ -1052,7 +1052,7 @@ gimp_export_exif (void)
  * gimp_export_xmp:
  *
  * Returns whether file plug-ins should default to exporting XMP
- * metadata, according preferences (original settings is #FALSE since
+ * metadata, according preferences (original settings is %FALSE since
  * metadata can contain sensitive information).
  *
  * Return value: TRUE if preferences are set to export XMP.
@@ -1069,7 +1069,7 @@ gimp_export_xmp (void)
  * gimp_export_iptc:
  *
  * Returns whether file plug-ins should default to exporting IPTC
- * metadata, according preferences (original settings is #FALSE since
+ * metadata, according preferences (original settings is %FALSE since
  * metadata can contain sensitive information).
  *
  * Return value: TRUE if preferences are set to export IPTC.
@@ -1153,7 +1153,7 @@ gimp_wm_class (void)
  * Returns the display to be used for plug-in windows.
  *
  * This is a constant value given at plug-in configuration time.
- * Will return #NULL if GIMP has been started with no GUI, either
+ * Will return %NULL if GIMP has been started with no GUI, either
  * via "--no-interface" flag, or a console build.
  *
  * Return value: the display name
diff --git a/libgimp/gimplegacy.c b/libgimp/gimplegacy.c
index cae03c5c14..9ab1eadfcf 100644
--- a/libgimp/gimplegacy.c
+++ b/libgimp/gimplegacy.c
@@ -70,7 +70,7 @@ static GHashTable *gimp_temp_proc_ht = NULL;
  * @copyright:                                 the procedure's copyright.
  * @date:                                      the date the procedure was added.
  * @menu_label:                                the label to use for the procedure's menu entry,
- *                                             or #NULL if the procedure has no menu entry.
+ *                                             or %NULL if the procedure has no menu entry.
  * @image_types:                               the drawable types the procedure can handle.
  * @type:                                      the type of the procedure.
  * @n_params:                                  the number of parameters the procedure takes.
@@ -123,7 +123,7 @@ static GHashTable *gimp_temp_proc_ht = NULL;
  * procedure will cause the GIMP core to lock up.</emphasis>
  *
  * Additionally, a %GIMP_EXTENSION procedure with no parameters
- * (@n_params == 0 and @params == #NULL) is an "automatic" extension
+ * (@n_params == 0 and @params == %NULL) is an "automatic" extension
  * that will be automatically started on each GIMP startup.
  **/
 void
@@ -209,7 +209,7 @@ gimp_install_procedure (const gchar        *name,
  * @author:        the procedure's author(s).
  * @copyright:     the procedure's copyright.
  * @date:          the date the procedure was added.
- * @menu_label:    the procedure's menu label, or #NULL if the procedure has
+ * @menu_label:    the procedure's menu label, or %NULL if the procedure has
  *                 no menu entry.
  * @image_types:   the drawable types the procedure can handle.
  * @type:          the type of the procedure.
diff --git a/libgimpbase/gimputils.c b/libgimpbase/gimputils.c
index 2ee1338973..3c0e093de7 100644
--- a/libgimpbase/gimputils.c
+++ b/libgimpbase/gimputils.c
@@ -1099,10 +1099,10 @@ gimp_flags_value_get_abbrev (GFlagsClass *flags_class,
  * gimp_stack_trace_available:
  * @optimal: whether we get optimal traces.
  *
- * Returns #TRUE if we have dependencies to generate backtraces. If
- * @optimal is #TRUE, the function will return #TRUE only when we
+ * Returns %TRUE if we have dependencies to generate backtraces. If
+ * @optimal is %TRUE, the function will return %TRUE only when we
  * are able to generate optimal traces (i.e. with GDB or LLDB);
- * otherwise we return #TRUE even if only backtrace() API is available.
+ * otherwise we return %TRUE even if only backtrace() API is available.
  *
  * On Win32, we return TRUE if Dr. Mingw is built-in, FALSE otherwise.
  *
@@ -1166,14 +1166,14 @@ gimp_stack_trace_available (gboolean optimal)
  * fails on Win32.
  *
  * The stack trace, once generated, will either be printed to @stream or
- * returned as a newly allocated string in @trace, if not #NULL.
+ * returned as a newly allocated string in @trace, if not %NULL.
  *
  * In some error cases (e.g. segmentation fault), trying to allocate
  * more memory will trigger more segmentation faults and therefore loop
  * our error handling (which is just wrong). Therefore printing to a
  * file description is an implementation without any memory allocation.
 
- * Return value: #TRUE if a stack trace could be generated, #FALSE
+ * Return value: %TRUE if a stack trace could be generated, %FALSE
  * otherwise.
  *
  * Since: 2.10
diff --git a/libgimpwidgets/gimpcolorbutton.c b/libgimpwidgets/gimpcolorbutton.c
index cd98af249b..8e03853d85 100644
--- a/libgimpwidgets/gimpcolorbutton.c
+++ b/libgimpwidgets/gimpcolorbutton.c
@@ -812,7 +812,7 @@ gimp_color_button_get_update (GimpColorButton *button)
  * @button:     A #GimpColorButton widget.
  * @continuous: The new setting of the @continuous_update property.
  *
- * When set to #TRUE, the @button will emit the "color-changed"
+ * When set to %TRUE, the @button will emit the "color-changed"
  * continuously while the color is changed in the color selection
  * dialog.
  **/
diff --git a/libgimpwidgets/gimpcolornotebook.c b/libgimpwidgets/gimpcolornotebook.c
index 5b77004e04..4e8afefe9a 100644
--- a/libgimpwidgets/gimpcolornotebook.c
+++ b/libgimpwidgets/gimpcolornotebook.c
@@ -511,7 +511,7 @@ gimp_color_notebook_remove_selector (GtkContainer      *container,
  * The @page_type passed must be a #GimpColorSelector subtype.
  *
  * Return value: (transfer none): The new page widget, if @has_page was
- *               #TRUE, or #NULL if @has_page was #FALSE.
+ *               %TRUE, or %NULL if @has_page was %FALSE.
  **/
 GtkWidget *
 gimp_color_notebook_set_has_page (GimpColorNotebook *notebook,
diff --git a/libgimpwidgets/gimpcolorselection.c b/libgimpwidgets/gimpcolorselection.c
index 43db69608a..7ef6e8971e 100644
--- a/libgimpwidgets/gimpcolorselection.c
+++ b/libgimpwidgets/gimpcolorselection.c
@@ -432,7 +432,7 @@ gimp_color_selection_set_show_alpha (GimpColorSelection *selection,
  *
  * Returns the @selection's @show_alpha property.
  *
- * Return value: #TRUE if the #GimpColorSelection has alpha controls.
+ * Return value: %TRUE if the #GimpColorSelection has alpha controls.
  **/
 gboolean
 gimp_color_selection_get_show_alpha (GimpColorSelection *selection)
diff --git a/libgimpwidgets/gimpcolorselector.c b/libgimpwidgets/gimpcolorselector.c
index 593d31c3bf..e59601bd06 100644
--- a/libgimpwidgets/gimpcolorselector.c
+++ b/libgimpwidgets/gimpcolorselector.c
@@ -241,7 +241,7 @@ gimp_color_selector_set_toggles_visible (GimpColorSelector *selector,
  *
  * Returns the @visible property of the @selector's toggles.
  *
- * Return value: #TRUE if the #GimpColorSelector's toggles are visible.
+ * Return value: %TRUE if the #GimpColorSelector's toggles are visible.
  *
  * Since: 2.10
  **/
@@ -288,7 +288,7 @@ gimp_color_selector_set_toggles_sensitive (GimpColorSelector *selector,
  *
  * Returns the @sensitive property of the @selector's toggles.
  *
- * Return value: #TRUE if the #GimpColorSelector's toggles are sensitive.
+ * Return value: %TRUE if the #GimpColorSelector's toggles are sensitive.
  *
  * Since: 2.10
  **/
@@ -332,7 +332,7 @@ gimp_color_selector_set_show_alpha (GimpColorSelector *selector,
  *
  * Returns the @selector's @show_alpha property.
  *
- * Return value: #TRUE if the #GimpColorSelector has alpha controls.
+ * Return value: %TRUE if the #GimpColorSelector has alpha controls.
  *
  * Since: 2.10
  **/
diff --git a/libgimpwidgets/gimpfileentry.c b/libgimpwidgets/gimpfileentry.c
index 56e8de87b7..ac910985f1 100644
--- a/libgimpwidgets/gimpfileentry.c
+++ b/libgimpwidgets/gimpfileentry.c
@@ -55,7 +55,7 @@
  * case the filename listbox of the #GtkFileChooser dialog will be
  * set to directory mode.
  *
- * If you specify @check_valid as #TRUE in gimp_file_entry_new() the
+ * If you specify @check_valid as %TRUE in gimp_file_entry_new() the
  * entered filename will be checked for validity and a pixmap will be
  * shown which indicates if the file exists or not.
  *
diff --git a/libgimpwidgets/gimphelpui.c b/libgimpwidgets/gimphelpui.c
index 5bd66361fe..418871b735 100644
--- a/libgimpwidgets/gimphelpui.c
+++ b/libgimpwidgets/gimphelpui.c
@@ -166,7 +166,7 @@ gimp_help_connect (GtkWidget    *widget,
  * elements in the GIMP user interface should, if possible, also have
  * a @help_id set for context-sensitive help.
  *
- * This function can be called with #NULL for @tooltip. Use this feature
+ * This function can be called with %NULL for @tooltip. Use this feature
  * if you want to set a help link for a widget which shouldn't have
  * a visible tooltip.
  **/
diff --git a/libgimpwidgets/gimppropwidgets.c b/libgimpwidgets/gimppropwidgets.c
index 4dab4c9dca..3a73e32d92 100644
--- a/libgimpwidgets/gimppropwidgets.c
+++ b/libgimpwidgets/gimppropwidgets.c
@@ -93,7 +93,7 @@ static void   gimp_prop_check_button_notify   (GObject    *config,
  *
  * Creates a #GtkCheckButton that displays and sets the specified
  * boolean property.
- * If @label is #NULL, the @property_name's nick will be used as label
+ * If @label is %NULL, the @property_name's nick will be used as label
  * of the returned button.
  *
  * Return value: (transfer full): The newly created #GtkCheckButton widget.
@@ -204,7 +204,7 @@ static void   gimp_prop_enum_check_button_notify   (GObject    *config,
  * property of type Enum.  Note that this widget only allows two values
  * for the enum, one corresponding to the "checked" state and the
  * other to the "unchecked" state.
- * If @label is #NULL, the @property_name's nick will be used as label
+ * If @label is %NULL, the @property_name's nick will be used as label
  * of the returned button.
  *
  * Return value: (transfer full): The newly created #GtkCheckButton widget.
@@ -802,7 +802,7 @@ static void  gimp_prop_radio_button_notify   (GObject     *config,
  * the specified enum property.  The @minimum and @maximum arguments
  * allow only a subset of the enum to be used.  If the two arguments
  * are equal (e.g., 0, 0), then the full range of the enum will be used.
- * If @title is #NULL, the @property_name's nick will be used as label
+ * If @title is %NULL, the @property_name's nick will be used as label
  * of the returned frame.
  *
  * Return value: (transfer full): A #GimpFrame containing the radio buttons.
@@ -1012,7 +1012,7 @@ gimp_prop_enum_label_notify (GObject    *config,
  *
  * Creates a pair of radio buttons which function to set and display
  * the specified boolean property.
- * If @title is #NULL, the @property_name's nick will be used as label
+ * If @title is %NULL, the @property_name's nick will be used as label
  * of the returned frame.
  *
  * Return value: (transfer full): A #GimpFrame containing the radio buttons.
@@ -1330,7 +1330,7 @@ gimp_prop_hscale_new (GObject     *config,
  * Creates a #libgimpwidgets-gimpscaleentry (slider and spin button)
  * to set and display the value of the specified double property.  See
  * gimp_scale_entry_new() for more information.
- * If @label is #NULL, the @property_name's nick will be used as label
+ * If @label is %NULL, the @property_name's nick will be used as label
  * of the returned object.
  *
  * Note that the @scale_limits boolean is the inverse of
@@ -3882,7 +3882,7 @@ static void   gimp_prop_expander_notify (GObject     *config,
  * Creates a #GtkExpander controlled by the specified boolean property.
  * A value of %TRUE for the property corresponds to the expanded state
  * for the widget.
- * If @label is #NULL, the @property_name's nick will be used as label
+ * If @label is %NULL, the @property_name's nick will be used as label
  * of the returned widget.
  *
  * Return value: (transfer full): A new #GtkExpander widget.
diff --git a/libgimpwidgets/gimpsizeentry.c b/libgimpwidgets/gimpsizeentry.c
index c51eabf350..b2826104a7 100644
--- a/libgimpwidgets/gimpsizeentry.c
+++ b/libgimpwidgets/gimpsizeentry.c
@@ -52,7 +52,7 @@
  *
  * For each field, there can be one or two #GtkSpinButton's to enter
  * "value" and "reference value". If you specify @show_refval as
- * #FALSE in gimp_size_entry_new() there will be only one
+ * %FALSE in gimp_size_entry_new() there will be only one
  * #GtkSpinButton and the #GimpUnitComboBox will contain an item for
  * selecting GIMP_UNIT_PIXEL.
  *
@@ -1557,7 +1557,7 @@ gimp_size_entry_eevl_unit_resolver (const gchar      *identifier,
  * @show: Boolean
  *
  * Controls whether a unit menu is shown in the size entry.  If
- * @show is #TRUE, the menu is shown; otherwise it is hidden.
+ * @show is %TRUE, the menu is shown; otherwise it is hidden.
  *
  * Since: 2.4
  **/