How to add Opera as a default browser

I use the newest RC release

I have a question: How to add Opera as a default browser

I downloaded opera from Opera repo a install.

When i click on link in Thunderbird they don’t open on any browser.

Check attachments in Thunderbird Preferences.
Click edit on top left of page, then preferences and then set up attachments.

Thx for replay.

I find your solution before your replay but i linked to wrong file in system.

Correctly path for Opera is /usr/bin/opera (file) not /usr/lib/opera