Have you ever closed a browser window by accident and really wanted to retrieve that page? Or, are there times when you have several browser windows open and want to save each of those windows, including all of the tabs you had opened? No problem, with Session Manager, a Firefox add-on.
To read about Session Manager, go to their documentation page: http://sessionmanager.mozdev.org/documentation.html
To download and install it to your Firefox browser, go to https://addons.mozilla.org/en-US/firefox/addon/2324
I would advise installing the add-on to your Firefox browser, reading the documentation, and also adding two very handy buttons to your browser menu bar: “Undo Close” and “Session Manager.”
The Undo Close button does just what it says it does. If you accidentally close a browser window, simply click this and the window will appear. Session Manager allows you to save sessions, save the current windows, and other advanced options.
If this sounds like an add-on that you would never use, think again. And remember the times you wished you could recover the window you just closed. Then remember Session Manager, download it, and install the two menu buttons.