User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0a1) Gecko/20110921 Firefox/9.0a1 Build ID: 20110921040206 Steps to reproduce: When trying to type something in location bar it replaces what I have typed with something else. Actual results: An example of this is after typing "http://" when pressing second "/" firefox replaces it with "facebook.com" (i expect this could be another site under other circumstances) and I can't continue typing what I was typing. Expected results: The expected behavior is that location bar suggests address in the drop-down, and I will be the one who will decide whether to select it or continue typing.

do you have browser.urlbar.autoFill set to true?

Yes, "browser.urlbar.autoFill" set to "true", when it is "false" url bar works normally.