The user interface for FF4 sucks, I had to uninstall it and re-download FF3.6. Most of the differences were merely irritating - like the right click menu changing the places of Open in New Tab and Open in New Window, which was totally stupid, but I could have gotten used to that. The one change I could not do without and could find no way to restore was their eliminating the Recent Pages button - some sites take forever to click back through with the Back button alone.