This is a Tip for facebook addicted friends :-) who wants to chat with his friends as well as he wants to work in fire fox so he can chat on the sidebar of the fire fox with out adding any new tab here is the process...
1. Go to “Bookmarks” menu in Firefox then click “Show All Bookmarks” or alternatively type short cut Keys ” Ctrl+Shift+B” It would bring you to the library of Bookmarks and History.
2. Select “Bookmarks Toolbar” under “All Bookmarks” in the left side corner.
3. Now go to “Organize” menu available in the upper menu bar in left side and click “New Bookmark”
4. Type these values:
Name: Facebook Chat
and Check mark on “Load this bookmark in the Sidebar” then confirm with Ok
5. Go to “View” menu of Firefox and under Sidebar click ” Bookmarks” it would bring you the sidebar of Bookmarks, then select Facebook chat and start chatting with your friends within Firefox in sidebar.