Working with tabbed browsing
in Mozilla Firefox, posted Oct 26th 2011
Tabbed browsing is an innovative feature that eliminates the need to open multiple browser windows. Instead, many web pages may be opened using the same browser window. To create a new tab in Firefox, press the "Ctrl" and "T" keys simultaneously at any time during a web browsing session, or click the small tab with a "+" sign on it on the rightmost side of the tab bar.
To close a tab, simply press the "X" icon on the tab; if there are a lot of open tabs, that icon may not be present, so you'll need to either select the tab you want to close, or right click on it to bring up the contextual menu and select "Close Tab".
If you mistakenly closed a tab and want to retrieve it, simply right click on any tab and select "Undo Close Tab". Alternatively, you can select "History" in the menu bar or in the Firefox menu button, and then navigate down to the "Recently Closed Tabs" submenu to view your recently closed tabs, and just click on the one you want to recover.