Rated 5 out of 5 stars

per PowerShot el ago. 13, 2015 ·

To have this to work in Firefox:
You have to manually go into about:config and changed - extensions.dictionary-switcher.autodetect to true. But some times I have to get in to about:config again to switch in on, off and on again to work, even if it's "on" in extensions.dictionary-switcher.autodetect. Then it work again to switches languages.

To do this on Thunderbird:

Go in to in Thunderbird: Options>Advanced>Config Editor set this as 'true'
extensions.dictionary-switcher.autodetect

I hope they will fix this. Also autodetect as I write does not work. I'm on Windows 10, and with a clean installed OS, and only two language installed in Firefox.

This switcher should had been an included part of Firefox and Thunderbird.