See bug 828562 comment 0 bug 828562 comment 1. We would like to keep track of how users are closing tabs. For each closed tab, we should track the method that was used to close it (mouse, pen, touch, keyboard, script... are there others?). Also, we would like to keep track of how users are opening tabs. For each opened tab, we should track the method that was used to open it (mouse, pen, touch, keyboard, script, initial tab... others?).