When turning on Display Area Groups and looking at the floorplan view, Area groups first appear with the outline of the AG as a light gray, and the occupied slices within the AG are a darker bluish hue. However, the occupied slices on the top and bottom are not completely rendered.
Also, as soon as I begin to scroll about the window, the AG will become a solid color, and sometimes when scrolling the outline of the entire AG is not rendered completely, leaving the AG as two colors.
This is a known problem. It is fixed in the next generation floorplanning tools.