Firefox 2.0: Start Browsing From Where You Left Off
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You can use this tweak in Firefox 2.0 so that everytime you open the browser, you will get all the sites which you were visiting when you last closed the browser.
It is available in the Tools -> Options -> Main
Switch to “Show My Window and tabs from last time” option in the drop down list.
Source: Firefox 2.0: Session Restore Tweak
Popularity: 3% [?]
Yes, but how do you switch it off? It’s really annoying!