#endif // wxUSE_SASH
-class WXDLLEXPORT wxMDIParentFrame;
-class WXDLLEXPORT wxFrame;
+class WXDLLIMPEXP_FWD_CORE wxMDIParentFrame;
+class WXDLLIMPEXP_FWD_CORE wxFrame;
// This class implements the layout algorithm
class WXDLLIMPEXP_ADV wxLayoutAlgorithm: public wxObject