diff --git a/include/wx/custombgwin.h b/include/wx/custombgwin.h
index 73890a4654..329589c7f2 100644
--- a/include/wx/custombgwin.h
+++ b/include/wx/custombgwin.h
@@ -10,6 +10,10 @@
 #ifndef _WX_CUSTOMBGWIN_H_
 #define _WX_CUSTOMBGWIN_H_
 
+#include "wx/defs.h"
+
+class WXDLLIMPEXP_FWD_CORE wxBitmap;
+
 // ----------------------------------------------------------------------------
 // wxCustomBackgroundWindow: Adds support for custom backgrounds to any
 //                           wxWindow-derived class.
diff --git a/include/wx/generic/custombgwin.h b/include/wx/generic/custombgwin.h
index 8004195498..d274313069 100644
--- a/include/wx/generic/custombgwin.h
+++ b/include/wx/generic/custombgwin.h
@@ -11,6 +11,9 @@
 #define _WX_GENERIC_CUSTOMBGWIN_H_
 
 #include "wx/bitmap.h"
+#include "wx/dc.h"
+#include "wx/event.h"
+#include "wx/window.h"
 
 // A helper to avoid template bloat: this class contains all type-independent
 // code of wxCustomBackgroundWindow<> below.