Rated 4 out of 5 stars
First I love this extension. When it works :-). I've got it working on all my other machines but there is one where when I try to log into the google calendar and click next, it sends me to a browser window, which displays a 405 error. It does not stay in the thunderbird tab as expected. I'm baffled.
Thunderbird 52.8.0. Google Calendar Tab 3.9