Comment 5 for bug 1501250

Double click is not meant to select a URL (there's an option in the right click menu for that), and adding colon to the list of word-chars won't fix it either. E.g. if you have a URL with a trailing dot (which strictly speaking could be a part of the URL, but usually denotes the end of a sentence) then double click will select that, whereas Ctrl+click or Right click -> copy URL won't consider that to be part of the URL.