How to Enable Save Tabs on Exit for Firefox 4
Fortunately, save, modify killing Firefox 4 is not removed, and it is disabled by default. There is no need to use add-on or extension of this feature. Not sure why the Firefox developers decided, but here’s how to save the closure of the tabs in Firefox.
1. Type about:config in the address bar and press Enter.
3. On the filter bar, type browser.showQuitWarning and press Enter.
4. You can either double-click it, change the value from false to true, or right click and select Modify.
This change takes effect immediately, without restarting Firefox. Now try to open, close Firefox 4 is a series of tabs and you will be prompted to save a.