I don't remember this being an issue before - but when I'm watching a film in iTunes, VLC or streaming via a browser - the energy saver kicks in and the screen dims. The sound continues but the OS believes the computer is inactive. I have to either change my settings in energy saver or move the mouse to stop the screen from going to sleep. Is this a glitch? Is there another way around this - or an app that knows when I'm streaming video in a browser or watching a film without using front row.