Recently Opera software has released Opera 18 Developer, which today has got another update. This build is based on Chromium 1622.7. Apart from fixing crashes and other bugs, Opera 18.0.1264 Developer update has added two new features. One, Opera menu now opens on mouse down and two, an option to create search engine with right click has been added to search field.
How to add DuckDuckGo Search Engine to Opera 18 Developer
Since Opera already comes with search engines like Google, Yahoo, Bing, Amazon and Wikipedia. For instance to add DuckDuckGo search engine to Opera, visit DuckDuckGo homepage, right click on search field and select Add as Search Engine.
Type name and keyword shown for dialog and click Create button. DuckDuckGo.com will be added and shown under Other search engines which you can’t make as default.
Download Opera Developer
You can find full changelog here.