Anyone else seeing this? I can't make it happen on demand, but about once a day, Opera 7.11 just drops some of the history list for a window in tabbed browsing. It's very strange when it happens - like I know that the Back Button should return me to the Active List on the forum here, but instead I'm out in left field somewhere and the Avtive List is nowehere to beseen on the history list.
Wish I could consistently reproduce this -- for a while I suspected going back to an earlier page and then creating a new "forward" page by clicking on a link or using a bookmark. Or maybe clicking on a link before there's a full page load. But so far, I just get surprised, seemingly at random.
If you're referring to the fact that sometimes the BACK button in Opera becomes disabled or occasionally brings you back 2 sites instead of one, this is apparently a known bug. It happens especially on pages that are graphics-intensive.