diff --git a/libgimpwidgets/gimpcolordisplaystack.c b/libgimpwidgets/gimpcolordisplaystack.c
index 51320484f9..76eac5b325 100644
--- a/libgimpwidgets/gimpcolordisplaystack.c
+++ b/libgimpwidgets/gimpcolordisplaystack.c
@@ -286,6 +286,7 @@ gimp_color_display_stack_reorder_down (GimpColorDisplayStack *stack,
 
 /**
  * gimp_color_display_stack_convert_surface:
+ * @stack: a #GimpColorDisplayStack
  * @surface: a #cairo_image_surface_t of type ARGB32
  *
  * Runs all the stack's filters on all pixels in @surface.