Hello, When closing Firefox, the window's size and position are saved correctly apparently (judging by xulstorage.json's content) but when I start Firefox again the window is shifted to the right by 10px exactly if the window was on the leftmost of the screen (x=0) when closed. If I close Firefox and the window is on the rightmost of the screen it shift it to the left by 10px exactly too. If I manually set the window to the whole width of the screen (not with the maximize button), the window is shifted 10px to the right. If the window is not on the leftmost or rightmost, the position is restored correctly/precisely. If the window is maximized, it is restored correctly (in its maximized state). I have checked this behavior with other applications (Chrome, Discord, Microsoft Outlook/Word/Excel) and they all restore their size/position correctly, no shifting. I have tried deleting xulstorage.json but the issue is still present, and it also happen on a fresh install/profile of Firefox (and Windows). '''Question:''' Is there a way to preserve the position Firefox's window so it is exactly at the leftmost or rightmost of the screen after a restart? Tested on Firefox version: 83.0, Fresh Install and Profile OS: Windows 10 20H2, Fresh Install, Default Display/Window Settings (Also tested on Windows Server 2016, same behavior).