1 files changed, 2 insertions, 2 deletions
diff --git a/src/extension/prefdialog.h b/src/extension/prefdialog.h
index 0c0bfcb88..f2ff60770 100644
--- a/src/extension/prefdialog.h
+++ b/src/extension/prefdialog.h
@@ -71,8 +71,8 @@ class PrefDialog : public Gtk::Dialog {
 public:
     PrefDialog (Glib::ustring name,
                 gchar const * help,
-                Gtk::Widget * controls = NULL,
-                Effect * effect = NULL);
+                Gtk::Widget * controls = nullptr,
+                Effect * effect = nullptr);
     ~PrefDialog () override;
 };