Use Dual-Monitor Feature with One Monitor
*Photoshop Lightroom 2 Tip*
Dual-monitor support also works if you're using only one monitor. With the Filmstrip open, click on the second monitor icon at the bottom-left. When the second display appears, resize it as necessary. Change the settings to Loupe and Zoom to Fit Screen, and then move the display to an area of your workspace where it isn't in the way of your retouching work. As you zoom in to work on the image, the second monitor display shows how the changes are affecting the entire photo.