Little Red Square on Platter Screen

Hi There,

What is the meaning of the little red square between the vinyl text and white ring inside the CDJ platter screen when slip mode is turned off. When i load different tracks the red square shows up in different spots.

Sorry if this is a noob question but i can find an answer anywhere other than the red ring when in slip mode.

thanks, 

here is a photo for reference

http://ryanruel.com/pics/cdj2000nexus3.jpg