Private browsing in Opera is not so private actually

I've always been using Opera's private browsing when didn't want any history and other stuff to be saved locally. Always until I decided to take a look at how private it really is.
After some private browsing I navigated to ~/.opera/temporary_downloads and noticed that Opera stores some necessary files there. There were:

• crossdomain.xml (which may reveal domain you browsed in many cases)
• various swf files (which may reveal sensitive information when decompiled)
• strange video_related.htm file, which contained a lot of info
  

That's fine, but the actual problem is that Opera doesn't delete the files when closed. It only do this when opened in next time. It works so regardless private or usual navigation. And I doubt anyone opens Opera again just to clear files after private browsing.
So, Opera's private browsing is not so private actually.