Hello, this add-on no longer works as it is a legacy add-on. This add-on was not developed by Mozilla, so its up to the developer of the add-on to update the add-on to WebExtensions format.

To find a replacement see this helpful website: https://mozilla.github.io/extension-finder/

More information: https://support.mozilla.org/en-US/kb/firefox-add-technology-modernizing

Thanks for using Firefox. If this solved your problem, mark as solution.

Nothing helpful on https://mozilla.github.io/extension-finder/ ... :( Is it really so difficult to make this function in the FF?

Contact the developer and tell him to update his add-on, we can't do anything from our end.

Developer doesn't answer... :( I asked you to do the same options in FF (not a plugin). Make it possible to use different languages in different tabs. If i changed language in one tab, it doesn't affect to others. It's possible?

The people who answer questions here, for the most part, are other Firefox users volunteering their time (like me), not Mozilla employees or Firefox developers.

If you want to leave feedback for Firefox developers, you can go to the Firefox Help menu and select Submit Feedback... or use this link. Your feedback gets collected by a team of people who read it and gather data about the most common issues.

Thank you very much!

If you have not done so, please choose the answer that solved your issue.

It's a bit late now, but in case anyone else finds this question looking for information on a TabLang replacement, you might like to try https://github.com/AlexVallat/KeyLayoutAutoSwitch

It isn't an addon (addons are no longer allowed the sort of deep unrestricted access that would be required), but if you don't mind having a small windows app running in the background, it can do the job.