That is the way the Compendium appears in Internet Explorer. The application is using IE for that window. So if you launch IE and go to the Compendium, that is what the menu looks like. So I do not believe it is an issue with this application, but with how IE renders the page. Nothing I can do about that.
Chrome seems to render the menu correctly. And I have not tried this, so have absolutely no idea if it will actually work. But if you load the Chrome overlay on top of IE, maybe then IE (and thus this application) would work???