Most important, most means most, feature that a browser must have is that it should crash when something went wrong.
This is the reason why I stop using firefox. And now, seems like Opera has the same problem. Even worse, I can say.
So, my advice is to set Opera to crash when is unavailable (it can't be used, it's not responding).
I hope you won't say that this is my problem cause I'm developer and i'm a bad programmer...
PS: Windows 7, 64 - Opera 49