show help for the page under mouse when the [?] button is used to request help

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@39342 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/bookctrl.h

@@ -222,6 +222,12 @@ protected:
     // Lay out controls
     void DoSize();
 
+#if wxUSE_HELP
+    // Show the help for the corresponding page
+    void OnHelp(wxHelpEvent& event);
+#endif // wxUSE_HELP
+
+
     // the array of all pages of this control
     wxArrayPages m_pages;