Why does my screen sometimes dim, apparently at random?

The Cintiq Companion is equipped with an ambient light sensor. If the ambient light in your location changes, the screen brightness will adjust to compensate. Sometimes your hand moving across the sensor will cause a momentary change. If you would prefer to turn off the ambient light sensor you can do so as follows:

1. Swipe from the right side of the screen to open the “Charms” menu
2. Select “Settings”
3. Select “Change PC Settings”
4. Select  “General”
5. Locate “Adjust my screen settings automatically”
6. Slide the slider under this option to “off”.