let the popup listbox process the kbd messages in wxComboBox

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@14698 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/popupwin.h

@@ -151,9 +151,13 @@ protected:
     // notify the combo here
     virtual void OnDismiss();
 
+    // forward the key presses to the combobox
+    void OnKeyDown(wxKeyEvent& event);
+
     // the parent combobox
     wxComboControl *m_combo;
 
+    DECLARE_EVENT_TABLE()
     DECLARE_DYNAMIC_CLASS(wxPopupComboWindow)
 };