A method and apparatus for aiding a user in identifying particular windows on a display screen. The amount of time each of the windows presented to the display screen is active (also known as "in focus") is monitored. Upon receipt of a command from the user, the windows that were active a longer length...http://www.google.com/patents/US5377317?utm_source=gb-gplus-sharePatent US5377317 - Method and apparatus for distinctively displaying windows on a computer display screen
