Google Advanced Search Improvement

I may be the last to realize this, but Google’s Advanced Search page has been AJAXified nicely, such that as you fill out the boxes that filter your search, you can see the search terms appear correctly formatted in the uppermost text box. This is, I suppose, a way of letting you correct whatever might have been wrongly entered, but also, I suspect a way of instructing people who want to learn how to build a complex search without the help of a form or a wizard.