Turn your favorite web pages into smaller, more manageable “apps” by pinning the pages to your browser’s tab bar. To pin a tab, right click on the tab, and click “Pin as App Tab.”
Group Your Tabs
Tab Candy gets an official spot in Firefox 4 with this feature that groups your tabs together for easy access. Just head over to the far right of your browser and click on the arrow, or the shortcut Command, Shift, E.
Sync all your passwords, bookmarks, and browsing history to your mobile browser with Firefox Sync. To activate, head to “Tools”, then “Set Up Sync.”
Tabs on Top
Tabs have been moved to the top of the browser bar, which lets you get an easy view of all your open tabs and App Tabs. You can still change this back to the old view (tabs below the browser bar) by heading to “View,” “Toolbar,” then unchecking the “Tabs on Top” setting.
Just like Chrome’s Incognito Window, Firefox 4 allows private browsing. When you’re in a private browsing session, Firefox won’t store browsing history, cookies, cache files, download history, passwords, or form autocomplete. To activate, head to “Tools,” then “Start Private Browsing.”