About this Add-on
It also includes:
— 4 spellchecker dictionaries (to choose from),
— a conjugation tool (which contains approximately 8000 verbs),
— a text formatter (to automatically correct most of typographical mistakes).
— a lexicon editor for your personal dictionary.
Grammalecte also exists for Firefox, LibreOffice and OpenOffice.
No support in the comments.
The version for Thunderbird 68 is available on Grammalecte website.
If you write your messages in text mode instead of HTML mode (default option), you must change the settings of each account in the panel [Composition and addressing] :
For [Composition], select [start my reply above the quote].