cleaner does not clear stored password of facebook

I'm using the latest version 4.16 and have been using ccleaner (free, sorry) for many years. Excellent product! I noticed that the facebook stored password is not cleared from the browser form (IE11 and Chrome 36). Granted, facebook can be storing the password in "some proprietary manner", however, in the case of IE 11, when I use IEs Delete Browsing History window and select all options it does clear the password. This leads me to believe it is a ccleaner "bug".