It really would be a great improvement to switch off the default horizontal tab bar. I've no idea why a side-bar tab interface replacement, appears to be so resisted by browser development. With wide, short screens, it's a massive user interface improvement for anyone that wants screen height to be used to display page content, rather than controls.

Agree entirely, the whole reason me to use Opera was the tab bar placement and the better handling of some sites, but without the tab bar placement, Opera is now waste of time for me.
I thought it was only the Redmond giant that invented new ways to annoy users.