All new functions now handle errors by raising IEExceptionMBS exceptions with error number and message set. We added over 50 new methods there to control HTMLViewer on Windows even more. Please let us know if you miss something.
An advantage of the new classes is that you can keep a reference to them in a property. Instead of us looking up the objects internally always, caching them will improve performance.
See also WKWebViewMBS, WebViewMBS, ChromiumBrowserMBS and LinuxWebViewMBS classes for other platforms. You may see the pattern, but instead of putting all methods directly on the HTMLViewer, we plan to move them all into classes and just give you a convenience method to get the instance for the given class.