RFC: http://area51.phpbb.com/phpBB/viewtopic.php?f=108&t=42707
The Full Editor button is kind of useless. There is really no point in returning to the full editor unless you wish to preview what you have written. Even if you want to just have access to the BBCode and Smilies, it doesn't hurt to preview automatically. So I propose changing the Full Editor button on the Quick Reply to Preview.