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
update to Opera 50 !
Protect your session against crashes
Upon a crash loop detection, Opera 50 will not remove your current browsing session. Instead, all pages will be marked for manual reload after re-activation, except for the current tab which will detail the encountered problem. This will fix the annoying issue of losing all opened tabs due to an unrelated problem such as with syncing, for instance.
l lurve this new 1 that came out..Opera Developer 52.0.2838.0 it is wicked ! esp with the new tab function.. Yes Yes ! !..