diff --git a/demos/testgtk/main.c b/demos/testgtk/main.c
index 69c872a2b6..bf43ca34ea 100644
--- a/demos/testgtk/main.c
+++ b/demos/testgtk/main.c
@@ -369,16 +369,16 @@ main (int argc, char **argv)
 			    gtk_label_new ("Source"));
 
   tag = gtk_text_buffer_create_tag (info_buffer, "title");
-  gtk_object_set (GTK_OBJECT (tag),
-		 "font", "Sans 18",
-		 NULL);
+  g_object_set (tag,
+                "font", "Sans 18",
+                NULL);
 
   tag = gtk_text_buffer_create_tag (info_buffer, "source");
-  gtk_object_set (GTK_OBJECT (tag),
-		  "font", "Courier 10",
-		  "pixels_above_lines", 0,
-		  "pixels_below_lines", 0,
-		 NULL);
+  g_object_set (tag,
+                "font", "Courier 10",
+                "pixels_above_lines", 0,
+                "pixels_below_lines", 0,
+                NULL);
 
   gtk_window_set_default_size (GTK_WINDOW (window), 600, 400);
   gtk_widget_show_all (window);