1 files changed, 3 insertions, 2 deletions
diff --git a/FL/Fl_Double_Window.H b/FL/Fl_Double_Window.H
index 46dd106f2..4ffcb65d1 100644
--- a/FL/Fl_Double_Window.H
+++ b/FL/Fl_Double_Window.H
@@ -23,6 +23,7 @@
 #define Fl_Double_Window_H
 
 #include "Fl_Window.H"
+class Fl_Overlay_Window;
 
 /**
   The Fl_Double_Window provides a double-buffered window.
@@ -44,8 +45,8 @@ public:
   /**
     Return non-null if this is an Fl_Overlay_Window object.
   */
-  virtual Fl_Double_Window *as_overlay_window() {return NULL; }
-public:
+  virtual Fl_Overlay_Window *as_overlay_window() {return NULL; }
+  virtual Fl_Double_Window *as_double_window() {return this; }
   void show();
   void show(int a, char **b) {Fl_Window::show(a,b);}
   void flush();