Current status (4/14/09)
Play with it and find the bugs. Save early and often. The only way to save is to switch to the ImpExp panel and copy/paste the config to your favorite editor. So, again, remember to save early and save often! (If lossage becomes a problem, I can always implement a timed, nagging pop-up.)
To import the configuration, the progam simply evals the content you paste into the text area. Normally, this is a security issue. But unless you are bent on doing malicious things to yourself, it's probably not a concern at all. This development script does not communicate with anything outside of your browser. Whatever playing you do with the tree will never appear anwhere else. If you reload the window, all your changes will vanish. This is still a test program!
This seems to work well enough in Firefox, Epiphany and Konqueror. IE does not work at all; this may be related to my use of .indexOf() methods. No browser detects and reports all EScript mistakes, though some are better at it than others.