I'm using Firefox for signage throughout multiple different displays of varying resolutions. I'm launching firefox through the cli with the command `firefox --kiosk {file}` and it seems as though Firefox will not open landscape (1080p) files in full screen. I regularly get the browser opening in smaller formats than they actually are and a dark gray border around the file; with one exception: A portrait graphic in the proper full resolution opens fullscreen correctly. I've tried looking through the preferences and can't find any place that would cause `--kiosk` to open in any size other than full screen. This seems to be an issue with any link or graphic that's not portrait, on a portrait screen. I've also tried different applications (ffmpeg, vlc, etc) and they have no issues adapting to the full resolution of the screen in either landscape or portrait mode, which leads me to believe this is a Firefox issue. The devices are reporting back the proper resolution and orientation of the screens as well. The only work-around I've found is to use a Pass-Through EDID on my 1080p screens, but that's not ideal as I'd rather not introduce more potential points of failure to this system. For reference I've attached pictures. 1. The picture with the QR code should take up ~50% of the diagonal screen real-estate. 2. The picture with the all-black graphic and gray border should just be all-black and fill the screen from top to bottom. 3. The picture of the portrait graphic is correct and what I would expect the all-black graphic to look like as well. 4. The picture of the "Groups" graphic with gray border shouldn't have the border and should fill the whole screen. This is also the screen that I attached the 1080p EDID Emulator to that has since been working correctly.