Firefox 4 has introduced an quick way to access frequently access websites. Most of the people keep open particular set of website all the time for example for checking mail or any social networking site. For one click access to such websites Firefox has introduced “App Tabs”, this allow to keep frequently used or favorite websites tabs available all the time on browser’s tab bar.
To add an app tab to you Firefox 4 browser just open corresponding web site , right click on tab and choose ”Pin as App Tab”.
After pinning any opened tab as App Tab, it will be always available with respective favicon.
As shown in above figure, these app tabs will serve as one click access to your favorite/ frequently used websites.