3 files changed, 9 insertions, 4 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();
diff --git a/FL/Fl_Overlay_Window.H b/FL/Fl_Overlay_Window.H
index 5114d3029..32ce7cfa4 100644
--- a/FL/Fl_Overlay_Window.H
+++ b/FL/Fl_Overlay_Window.H
@@ -72,7 +72,7 @@ protected:
   Fl_Overlay_Window(int X, int Y, int W, int H, const char *l=0);
 public:
   void show(int a, char **b) {Fl_Double_Window::show(a,b);}
-  virtual Fl_Double_Window *as_overlay_window() {return this; }
+  virtual Fl_Overlay_Window *as_overlay_window() {return this; }
 };
 
 #endif
diff --git a/FL/Fl_Window.H b/FL/Fl_Window.H
index 88b3a0737..9dd443e8e 100644
--- a/FL/Fl_Window.H
+++ b/FL/Fl_Window.H
@@ -37,7 +37,7 @@ class Fl_X;
 class Fl_Window_Driver;
 class Fl_RGB_Image;
 class Fl_Shared_Image;
-
+class Fl_Double_Window;
 
 /**
   This widget produces an actual window.  This can either be a main
@@ -637,6 +637,10 @@ public:
   void capture_titlebar_and_borders(Fl_Shared_Image*& top, Fl_Shared_Image*& left, Fl_Shared_Image*& bottom, Fl_Shared_Image*& right);
   Fl_Window_Driver *driver() { return i; }
 
+  /**
+   Return non-null if this is an Fl_Overlay_Window object.
+   */
+  virtual Fl_Double_Window *as_double_window() {return NULL; }
 };
 
 #endif