It is controlled by a configuration option in "MediaPortal Configuration"; see this page in the Wiki:Can these be changed
MediaPortal is used all over the world, and there are significant differences between the TV systems that MediaPortal has to deal with. This makes MP more complicated than would be the case for software intended exclusively for the UK.Like many things I've noticed with new MP journey, even basic things require configuring, doesn't work how you would expect out of the box.