Mozilla added a function to search on the web in the latest versions of Thunderbird.That's nice, but the default search engine is bing. As a DuckDuckGo user, I wanted to add my favourite search engine and use it by default. So here's how to do it.

1. Find your profile folder.
2. In it, create a folder named "searchplugins" (without the quotes) if it doesn't exists.
3. Save this xml file in it.
4. (Re)start Thunderbird.
5. Select some text in any mail, right clic and search with bing (sorry).
6. Click the DuckDuckGo icon on the left.
7. Click the heart icon on the bottom left.
8. That's all!

To add google, add this file in the same folder.