Multiple monitors, vertical set up. Whenever the window is maximized there is white bar that bleeds into the top monitor. Going to to full screen using F11 gets rid of this bar. Same behavior in troubleshoot mode, Same behavior with default theme, Same behavior with no extensions. I'm using Windows 10 and Firefox Version 89.0.2 (64-bit) Found a previous post with the same issue and no solution. They say this bug has been present since Firefox 79. Post was archived so I'm making a new one. [[https://support.mozilla.org/en-US/questions/1297501|https://support.mozilla.org/en-US/questions/1297501]] Normally this doesn't cause an issue but if I'm watching something in full screen on the top monitor and click on Firefox then it will appear.