https://addons.mozilla.org/en-US/thunderbird/addon/5467

This Thunderbird extension allows you to directly use FireFox to search
the web for content in a newsgroup post. For example, Larry Jaques
recently wrote, in part:
"Oh, after spending far too much on some Maas metal polish via mail
order, I noticed it on the Wally World shelves."
To search for "Maas metal polish" on web, I simply selected it in
Larry's post & clicked on "Search for ..." in the right-click menu. The
extension went to FireFox, opened Google, and searched for "Maas metal
polish". Neat!

Bob

BTW - it uses your default search engine, which happened to be Google
for me.