Quick Edit allows an editing control to be opened up directly in the thread. If the user's browser doesn't support Quick Edit, the user will be taken to the normal editing screen. User's may go to the Advanced Editor at any time by pressing the 'Go Advanced' button at the bottom of the editor. Users will need to go to the Advanced Editor to utilize the editor tool bar. The advantage of the Quick Edit is that the user is not taken to a new page to edit the post and when the user is done, the post is modified without any new page loads.
The quickedit feature is back now and it's now a UserCP option.
It is turned on by default now...If you have problems with it you can turn it off in your UserCP: http://filesharingtalk.com/vb3/usercp.php?