I don't think I've ever had this kind of problem before with any application. I installed Opera just to see if they were offering anything new, and when I discovered that they weren't, I uninstalled it. By uninstall, I mean I dragged it into Appzapper, emptied my trash, and continued working.
A few days later, I double click a torrent file... and it opens in Opera! Yes, the same application that I already uninstalled. How is this possible? I did a spotlight search and found nothing but a left over icon file which I quickly deleted. And yet it still starts up every time I double click a torrent. It's not in my Apps folder, utilities, or anywhere else.
Any explanation?