I have had this problem for months, still do on Feb. 29th, 2016. Seriously, Opera, how often do you want to know that I am friends with you. Yes, I still want you as my default browser. Yes, today as well. Yes, this evening, too. Yes, I like you. Ok, stop asking, Opera, you're making me upset...
Anyway, I'm wondering if Chrome on Ubuntu (which I use for Netflix) sneakily makes itself default?
Version: 35.0.2066.82 - Opera is up to date
Update stream: Stable
System: Ubuntu 15.10 (x86_64; Unity)