>>> My Info: Win7_64, Nightly 52, 32bit, ID 20161028030204 (2016-10-28) STR_1: 1. Open https://www.iandevlin.com/html5test/webvtt/html5-video-webvtt-sample.html , play the video 2. Focus play button in video 3. Press Spacebar AR: Video stops, then starts playing ER: Video should stop. STR_2: 1. Open https://www.iandevlin.com/html5test/webvtt/html5-video-webvtt-sample.html , play the video 2. Focus closed captions button in video 3. Press Spacebar AR: Video stops AND closed captions toggle ER: Only 1 action for Spacebar, preferably "Stop the video" STR_3: 1. Open https://www.iandevlin.com/html5test/webvtt/html5-video-webvtt-sample.html , play the video 2. Focus timeline in video (via Tab key) 3. Press Down/Up AR: Volume decreases/increases, but also the video jumps 0.1s back/forward ER: Only 1 action for Down/Up, preferably "Volume should decrease/increase" Note: This is marked as blocking for bug 1271765, because STR_1 and STR_3 were added in that bug STR_2 was added in bug 887934, I guess. But I think they all should be considered as 1 bug.

The root cause is that I failed to retain the consistent of its focusability in Bug 1271765. I think this is a same/similar bug to Bug 1325594, these controls have to refrain from being focus. Thank you so much arni2033.