Described is a method and system for power management of mobile computer displays, in which areas of the screen are selectively controlled to consume less power than other areas. For example, a foreground window having focus may receive normal brightness, while background areas are dimmed. To this end, the pixels of selected areas are controlled to vary color depth, resolution, refresh rate, brightness and/or the on/off state for any part of the display. Power settings for parts of the display not corresponding to a focused window can be gradually reduced over time. Power policy may determine which areas are given reduced power, and external mechanisms provide information useful in the determination, such as when the user last interacted with a window, where the mouse is hovering, explicit user instructions as to how to power manage a window, and sensors that detect where the user is likely to want more power.