Rated 5 out of 5 stars

I used to use this addon on older versions of thunderbird. I tried to port it to the new version but was unable to get the exact functionality working.

Instead, I wrote a new addon which adds a new custom Reply All button that will behave as expected and can be used to replace the SmartReply button in the message actions list:

https://addons.thunderbird.net/eN-US/thunderbird/addon/reply-all-button/