1. A non-transitory computer readable medium containing program instructions for causing a computer to perform the method of: accessing data representing displayable content; displaying a representation of said displayable content on an operator display; displaying said representation of said displayable content on a secondary display; manipulating said representation of said displayable content on both the operator's display and the secondary display in response to user input; and displaying operator-specific content on the operator's display, wherein said operator-specific content is not visible on the secondary display, and wherein said operator-specific content overlaps with the area of the operator display containing said representation of said displayable content.