diff --git a/src/mgl/app.cpp b/src/mgl/app.cpp
index c6fab2dc9b..da9471e4dc 100644
--- a/src/mgl/app.cpp
+++ b/src/mgl/app.cpp
@@ -142,9 +142,13 @@ class wxRootWindow : public wxWindow
             m_wnd = NULL; 
         }
 
-        virtual bool AcceptsFocus() { return FALSE; }
+        virtual bool AcceptsFocus() const { return FALSE; }
+        
+        DECLARE_DYNAMIC_CLASS(wxRootWindow)
 };
 
+IMPLEMENT_DYNAMIC_CLASS(wxRootWindow, wxWindow)
+
 static wxRootWindow *gs_rootWindow = NULL;
 
 //-----------------------------------------------------------------------------