Make sure you enable yours by right-clicking on your desktop and selecting Display settings. Select the monitor you want to tweak the settings for, and use the resolution drop-down to select your ...
6. Close the lid and use the monitor with your keyboard and mouse. The display behavior on MacOS is a bit different than that on Windows. You don't have to change your lid settings. However ...
Automatic Gain Control (AGC): This feature controls the brightness of dark or bright signals. If AGC is causing issues, set the AGC level to 0, especially in Cinema mode. This can be done by accessing ...