Power Saver function enables and disables itself
I'm using Opera Developer version ,,39.0.2234.0". When I start Opera in laptop without laptop being plugged-in, power saver icon is disabled. In order to enable Power Saver, it gives me from time to time automatically an tooltip to enable Power Saver or I have to enable Power Saver manually.
How can I enable Power Saver function so that it is enabled automatically after starting Opera, when laptop is not plugged-in?