Please make sure to finish all your posts before this time. The downtime should only last for a few minutes.
I can not make the default search engine?
Why I can not add your own default search engine?
This is an important shortcoming.
You can add but not make it default because of security reasons.
Because of that, please read: https://forums.opera.com/post/46190
Closing as a duplicate topic (of many others not just the one linked).
Someone could post a request about this funcionality in the suggestion box, but believe me they're already fully aware of that request...