In FF3 they decided to be clever, and match on the substring, not only in the URL but in metadata. The annoyance I felt when Microsoft products started capitalizing things I'd typed in lower case (and then would sometimes re-capitalize them after i manually reverted to lower case) is as nothing compared to this.
According to this tip, this misfeature can be turned off, reverting to the FF2 behaviour. The tip is a lie.
Here is my FF3 showing that setting, set to 2 as per the tip — a change I made a couple of weeks ago:
And here is what actually happens when I type "camb" into the stupid bar:
Only the items 4 and 6 are for sites in domains starting with "camb" — the other four, including the top three results, sure as hell appear to have been generated by the stupidity this setting is supposed to turn off.
I don't want an idiot bar in my browser: I want a location bar. If I wanted my computer to override my typing with its own stupid guesses, I'd use Microsoft products. Does anyone know how to actually bury this misfeature and drive a stake through its heart?