>>> My Info: Win7_64, Nightly 49, 32bit, ID 20160526082509 STR_1: 1. Open http://imgur.com/xZt0Z1t 2. Hover mouse over the video 3. Doubleclick w/o releasing left mouse in the end, then drag mouse by ~5px AR: Title of image is selected ER: Irrelevant text shouldn't be selected: I moved mouse pointer by 5px, far away from that text
Tested on Windows 10 x 64 with Fireox Nightly 49 and Firefox Nightly 54.0a1 and I can reproduce it.
Too late for firefox 52, mass-wontfix.