>There are various options which may turn off that feature. However, I have found out that this autocomplete stuff only applies to the same URL, thus not the same page. You can have the same page, but with a different URL. This happens when you have a query string that it attached to the URL which may vary from one hit to another. If the page is accessed as is, the autocomplete should work. Otherwise, it won't because the browser thinks it is a different page.

A query string is considered part of the the URL. I don't think you can expect a browser to chop arbitrary bits off the end in order to decide whether it is the same URL for auto-complete purposes - it's perfectly possible that just differences in query strings could generate completely different pages.