I watch movies on Youtube, Popcorn or XBMC and after 10 seconds when I have my laptop disconnected from power the screen dims. I know that there is an option in
dconf-editor for longer timeout but does not suit me. There is the option in
power-manager to disable the screen dimming on battery/ac but I wouldn't like that option.
I would like something like caffeine but it does not work in Ubuntu MATE 15.04.
What should I do? It's annoying to disable screen dimming manually every time I watch a movie or video.