I am using Opera 10.51. When it opens more than one tabs, "Aero Peek" preview of Windows 7 will show all of them —- it wastes me one click, because I always clearly know what I am going to do.
How to turn it off?
In Opera address bar, "opera:config", select "Show All", find "Use Windows 7 Taskbar Thumbnails" item, uncheck it, and save. Restart Opera, it works as I wish!