Hi, I have a brand new iMac 5K but one thing that's driving me crazy is that it keeps automatically adjusting the brightness (to a low level). This happens even though I have 'Automatically adjust brightness' in SysPrefs->Displays set to off (Unchecked). Is anyone else experiencing this problem? I'm running the latest El Capitan (10.7.5) and I have no idea why it is ignoring the Auto-brightness setting. It always want to take it to around 25% brightness level around sunset so I can barely see the screen.