Some tipps Rated 3 out of 5 stars

I haven't tried this extension yet, at the moment I'm using Header Tools Lite https://addons.mozilla.org/thunderbird/addon/header-tools-lite/ to set the References-header manually.
In the description of that extension I found this:
Some IMAP servers, such as Gmail, do not accept changes if some basic headers (date, sender, the message id, object) are not modified . With the option “Forcing changes with IMAP accounts enabled“, the changes are forced by changing the date of the message of 1 second.

For me it is not working. Rated 3 out of 5 stars

Sounds great. But it is not working for me.

When I am selecting few messages and pickup option "rethread" last selected email is duplicated and nothing more.

Anybody else with similar issue?

Rated 5 out of 5 stars

Extra points for multiselect ;)

For mouse/keyboard dnd, perhaps TotalMessage may be of interest. Original references are stored and a backup is made to Trash if desired.