I asked this about 6 months ago and got no responses, but perhaps with the prices going falling on high-resolution monitors, someone has found a solution to this minor issue. What happens is that when I click the full screen mode for a YouTube video that has up to 4k resolution available, it goes to my native 2560x1440, but at the same spot, on every high-res video, the video will drop the resolution to 480p and exit full-screen mode. I then have to stop the video, change the resolution, and wait for about 20 sec. for everything to catch back up and the video to start playing. No problems after that. I'm not that hopeful, seeing that I got no responses before, but I thought I'd try one more time. I realize that this is a minor issue, and not exactly something that would affect more than a tiny handful of people.