A few months' ago I installed Opera Developer after seeing a positive write up and I have used it on Ubuntu 1404 LTS on an occasional basis (Firefox is my basic browser) and it is very fast. I think I started around version 38 and with regular updates, it is now at 40.0.2280.0.
It was only a couple of weeks or so ago (probably after one of the updates) that I first experienced this error message when clicking to open Opera :

"The login keyring did not get unlocked when you logged into your computer. Password ..../ cancel/ unlock"

I just hit cancel and Opera opens fine. Since I never use a login password, why would a request to start Opera suddenly have started producing this error a couple of weeks or so ago ?

Is it connected with some requirement for Opera to use the Gnome Keyring Daemon ? I have always had this disabled at startup because it has a history of interference with GnuPG.