From MozillaZine Knowledge Base

Background

Firefox 2.0 introduces a built-in Session Restore feature, allowing the user to continue browsing from where they left off if browser restarts. Since this feature lends itself well to keeping track of data about tabs and windows, it’s also used for re-opening recently closed windows. This preference controlled how many closed windows are kept track of via the Session Restore service, but the ability to restore windows was never exposed in the UI.

Possible values and their effects

A positive integer indicating how many window closures to remember for later possible restoration. (Default is 10)

Caveats

• The Session Restore service must be active for window data to be remembered.

First checked in

• 2006-04-26 by Mike Connor

Has an effect in

• Mozilla Firefox (nightly builds 2006-04-26–2006-07-22)

Related bugs

• Bug 328154 - Restore User's Session on App Launch
• Bug 328159 - Wire up the Session-data Service
• Bug 344642 - [SessionStore] Get rid of unused "Undo Close Window" code
• Bug 360408 - [SessionStore] Add 'Recently Closed Windows'/'Undo Close Window' (or make API easier on extensions)

Related preferences

• browser.sessionstore.enabled
• browser.sessionstore.interval
• browser.sessionstore.max_tabs_undo
• browser.sessionstore.resume_from_crash
• browser.sessionstore.resume_session
• browser.sessionstore.resume_session_once

External links

• Session Restore - MozillaWiki