Firefox 108 improved integration of the Window menu with Mac OS features related to tiling and moving windows between displays. However, this also caused the Window menu to show windows in alphabetical order based on the current tab title rather than the previous method of the order the windows were opened. You can manually work around this change by assigning specific window titles using the following add-on: https://addons.mozilla.org/firefox/addon/window-titler/ But if you don't want to do that manually, this add-on auto-numbers your windows, sequentially, to help keep their position stable on the Mac OS "Window" menu. Permissions No permissions are required for numbering, but storage is used to keep track of whether you want windows to be auto-numbered. Tabs permission is required for the optional toolbar buttons Windows list (check screenshots) Considerations If you close a window and re-open it, it will be assigned a new id number by Firefox and appear in a new position. In case your window numbers go missing, you can use the Tools menu, Renumber windows now command, to renumber them or in version 0.5+, use the toolbar button to access the same command. Feedback Needed! Since I'm a Windows user, I need your input on issues with the add-on. Please email me at jscher2000@outlook.com or create a new Issue on https://github.com/jscher2000/firefox-window-autonumber/issues