User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:41.0) Gecko/20100101 Firefox/41.0 Build ID: 20150705004008 Steps to reproduce: 1. Type a letter which the location bar auto-fills on. E.g. type "y" and get auto-filled with "youtube.com" 2. Press backspace to delete the auto-filled part of the URL. E.g. "youtube.com" becomes "y" again. 3. The "Visit youtube.com" option will still be highlighted in the list, suggesting pressing Enter will activate this option. 4. Press Enter, nothing happens. 5. Even after going up and down, reselecting the "Visit ..." option. It doesn't work anymore. This is another part of the same bug: After step 4, press Down to select another URL. Pressing backspace on this URL will trigger the URL. It basically triggers the very next thing that is typed in the location bar, buffering the Enter key or something. This bug does not happen when using the Delete key instead of backspace. Although even with Delete the "Visit ..." option stays highlighted. Which you'd expect not the be the case, because it doesn't trigger the "visit".