HTML_TreeMenu - what does dynamic really do?

Richard, I was looking at TreeMenu for building a file tree navigation (for a very large number of files - in a heavily nested filesystem) - obviously loading the whole tree up like the map_fs.php example would probably kill most browsers.. So I was wondering if the dynamic flag meant that when you expanded nodes (with children but not loaded on the page) it could either (a) refresh the page - or (b) pull the data into a iframe or something and add the data from there... (b) would be nice.. :) Regards Alan