I do not think “that bookmarks always override the active tab” is a problem in itself. When you open bookmarks, you need to realize that bookmarks is in itself an html file, sort of like a webpage.
The problem as I see it is more like Opera still sucks a bit in the way it manages the bookmarks file, because when you open bookmarks it goes out of context and you completely lose sight of what you had on screen (browser tabs and open webpages). What I mean with this is that bookmarks should open enclosed in a tab, very much like the Chrome browser does it. If done this way, you could keep a tab open with bookmarks at all times, and open from there whatever bookmarks you'd need without inconveniences.
