Thanks, As a Linux user, I found middle-clicking to paste a URL anywhere in the page to be the most annoying feature ever.
Middle click is pasting in X-windows, so when you are trying to paste text, and are just outside of the text box and firefox tries to open it as a URL, it is frustrating.
So your post helped me…but for the opposite reason, I couldn’t figure out which setting turned it off 🙂