Hi Marsio, thanks for the feedback - it's of course annoying that it does not seem to work for you, and I would like to try and help.
Could you check that all the needed permissions are granted so that the extension can function properly?
If you right-click on the extension's icon in your Firefox add-ons bar and click 'Manage Extension', then look for the 'Permissions' tab and ensure all the toggles are switched ON.
None of your data ever leaves your machine (it runs 100% locally), but without these permissions, the extension cannot access the ChatGPT page to trim the messages or verify the extensions authenticity. Without this access, the lag-fixer remains inactive.
