Although it has an API compatible with other help controllers, it has more advanced features, so it is
recommended that you use the specific API for this class instead. Note that if you
use .zip or .htb formats for your books, you
-must add this line to your application initialization: {\tt wxFileSystem::AddHandler(new wxZipFSHandler);}
+must add this line to your application initialization: {\tt wxFileSystem::AddHandler(new wxArchiveFSHandler);}
or nothing will be shown in your help window.
\end{itemize}