Bug 1119 - Mac: Window menu's list of open windows not available

src/AudacityApp.h

@@ -69,6 +69,10 @@ class AudacityApp final : public wxApp {
    // A wrapper of the above that does not throw
    bool SafeMRUOpen(const wxString &fileName);
 
+#if defined(__WXMAC__)
+   void OnWindow(wxCommandEvent &event);
+#endif
+
    void OnReceiveCommand(AppCommandEvent &event);
 
    void OnKeyDown(wxKeyEvent &event);