I have added many new features in this release (see release notes), including the ability to show the page (title, host, url) the formfield was first and/or last used.
The page a formfield originated from is obtained by examining the browse history. So in order for this to work, Firefox's "Remember browsing history" must be turned on. If browse history is available around the time the formfield was first or last used, the originating page can be obtained from the history database (places.sqlite). This however may not always be accurate! When a page is loaded by the browser, it is stored in a database along with the current date and time. The data for a formfield however, is not stored until it is submitted. This will always be some time after the page has been loaded. If the user loads a second page for instance in another tab, submitting a form in the first page will result in formfields being registered right after the second page was loaded. In this scenario Form History Control will link the incorrect page to the formfield.
In order to get a slightly simpler look I decided to get rid of the "Show only matching cleanup criteria" checkbox and replace it with a button under the cleanup tab.
For a complete list of changes, see Release Notes.
[update 23 Oct 2010]
Version 1.2.7 has been reviewed and is publicly available as of 22 Oct.