diff --git a/fluid/custom_widgets.h b/fluid/custom_widgets.h
index 36abc1414..875496b8e 100644
--- a/fluid/custom_widgets.h
+++ b/fluid/custom_widgets.h
@@ -1,7 +1,7 @@
 //
 // Shortcut header file for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2010 by Bill Spitzak and others.
+// Copyright 1998-2023 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -84,8 +84,7 @@ public:
     vars_user_data_ = user_data;
   }
 
-  int handle(int) override;
+  int handle(int) FL_OVERRIDE;
 };
 
 #endif
-