Avoid brightness reduction
By default, when the computer is inactive for 120 seconds the screen brightness is automatically reduced. This is a great idea, except that the brightness is also reduced when playing a video file with VLC, suddenly everything gets darker and is annoying to move the mouse every 2 minutes to restore the brightness level. So to fix this all we have to do is get rid of this option. Open the Power Manager Settings and then on the " On AC " and " On Battery " sections select the Monitor tab. Adjust the third slider all the way to the left, as shown in the picture bellow. Related posts: Edit Xfce Settings with graphical interface