I obviously hope that this integration can be achieved as soon as possible, but in the meantime I suggest the good KDE Crow Translate application, which allows you to quickly translate selected text by opening it in a separate floatable window. https...
There are very few addons on Thunderbird that allow the translation of emails and all of these, due to permission problems, can only open a separate window to show the translation of the text.An integrated translator that allows you to maintain the f...