Extensions were the big news when the Norwegian browser-maker announced an alpha (or pre-beta) of its version 11 browser. This brought the Opera browser in line with competitors like FireFox and more recently Google Chrome and and Apple Safari.
In this new beta, tab-stacking is the key feature.
"Tabs are the most popular feature in browsers today," said Jan Standal, vice president of desktop products for Opera.
"Because so many of us wrestle with tens or even hundreds of open tabs, we needed a way to simplify tab management. Just like stacking papers for future reference, stacking your tabs is an intuitive way to organize and collect your open web pages."
Also new for Opera 11 is an interface for "mouse gestures," which the browser has included since version 5.
These let users navigate, open new windows, and more with clicks, drags, and mouse wheel spinning instead of having to press buttons or choose menu options.
The company claims that in the three weeks since the capability was introduced, more than 500,000 extensions have been downloaded.