For some reason that is completely unfathomable to me, the URL that's shown as hilighted in firefox's URL window can get out of sync with options that show up in the drop down menu of possible alternatives, yet firefox gives preference to the drop down menu when you hit the TAB key to complete.
Case in point: I want to go to gmail. I start typing in "http://www.g" and the drop down shows up. The first thing its got highlighted is "http://www.google.com/", which makes sense. I next hit "m" (so what I got in the URL window is "http://www.gm")... the text in the URL window goes ahead and auto-completes out to "http://www.gmail.com", BUT the drop down highlight remains on "http:"//www.google.com/").
So when I hit ENTER, I'm being queried for a search string instead of looking at my inbox.
I sigh and once again curse my blazing fast touch typing skills and lightning quick ENTER key pressing reflex. So I go fumble around for the mouse, point the stupid pointer over the URL, double click to highlight the entire URL, hit BACKSPACE, and... we go back to where I said "Case in point:" up above.
Repeat 3-4 times until I finally am able to remember to force myself to stop and wait for the drop down to catch up and get to my email so I can read the latest chain letter my old high buds have forwarded to me.