Home button/finger scanner annoyance

Have anyone notice long pressing on the home button/finger scanner would trigger google now? Since I don't use google, I've disable it. My problem is that now when I hold onto the scanner it auto launch opera Web browser. My reason for holding onto the scanner is that some app I use requires finger unlocking. Most times it would just launch Opera instead off reading the finger. I'm currently on stock rom without root and would like to stay that way. If anyone know how to disable opera from poping up I would be very grateful. Thanx