In Windows 7 and Windows 8, there's a setting called "Dim display after" to control how long of an idle before the display dims (but not yet turn off). I have a Surface pro, I just upgraded to 8.1 and this function just disappeared. In Windows 8.1, I can't find this setting anymore.My Surface had the option to control the dim idle time under the advanced power settings dialog in Windows 8. But in Windows 8.1 that setting is missing. What's even more strange is that the setting to control the brightness of the screen when it's dimmed is still there--it's just the idle timeout for dimming that's missing. In both cases. Is anyone else seeing this? Is this a bug?