Linux XFCE desktop environment: Half-screen maximized Firefox is one pixel too high

I'm using XFCE on Ubuntu 22.4.04, and can also reproduce this on an XFCE desktop running in Debian on Termux in Android. The maximized window placement for Firefox in XFCE is incorrect. It overlaps the top titlebar by one pixel. Here is a screenshot of a maximized text editor (left) and Firefox (right). Firefox's 1-pixel tall gray outer top border is hidden below the XFCE panel. This is noticeably incongruent with the GTK window to the left, which retains its top border separating it visually from the panel. To confirm that part of the Firefox window is, in fact, overlapping, here is the non-maximized Firefox showing the gray top border, hidden in the previous image below the panel: My current "fix" is a bit sad: Create an invisible panel 1 pixel taller to push both windows down 1 pixel, and choose a desktop wallpaper that blends in when it peeks out through this 1px transparent region above GTK windows. This is a bit silly. Also, if Firefox windows are in the background, they will be visible in this 1px tall space above half-screen maximized windows, so it isn't even a complete visual fix. How can I adjust things for this to work better? Can I patch Firefox in userChrome.css? Fake the information X11 is sending it? Or would I need to patch the source and recompile?