I have an iPod Touch 3G. Not sure of the firmware. Over the past couple of days, the slider bar at the top of the screen when one is listening to music or podcasts has gone missing. So, I can no longer navigate to a specific point in a music track or podcast. To clarify, this is the navigation slider at the top of the screen, and also has an option to go back in the track by 30 seconds. Any ideas as to how I can get this feature back?