diff --git a/cellrendererspin.c b/cellrendererspin.c
index 85d3bda690c90272..f68f28971f136d86 100644
--- a/cellrendererspin.c
+++ b/cellrendererspin.c
@@ -73,8 +73,8 @@ static GtkCellEditable *gui_cell_renderer_spin_start_editing (GtkCellRenderer
                                                               GdkEvent             *event,
                                                               GtkWidget            *widget,
                                                               const gchar          *path,
-                                                              GdkRectangle         *background_area,
-                                                              GdkRectangle         *cell_area,
+                                                              const GdkRectangle   *background_area,
+                                                              const GdkRectangle   *cell_area,
                                                               GtkCellRendererState  flags);
 
 struct _GCRSpinInfo
@@ -307,8 +307,8 @@ gui_cell_renderer_spin_start_editing (GtkCellRenderer      *cell,
                                       GdkEvent             *event,
                                       GtkWidget            *widget,
                                       const gchar          *path,
-                                      GdkRectangle         *background_area,
-                                      GdkRectangle         *cell_area,
+                                      const GdkRectangle   *background_area,
+                                      const GdkRectangle   *cell_area,
                                       GtkCellRendererState  flags)
 {
   GtkCellRendererText *celltext;