If you open the link inspector and type "http://" in the page search field, the link inspector switches your input to the external link tab, which is helpful. However, it also moves your cursor from after the "http://" to before it.
Setting the priority as high because abruptly moving the user's cursor while they're typing is a serious usability issue. Feel free to lower if that's too high.
Seen on the Beta cluster on Firefox 37.0.2.