Adobe Audition CS6

When I am editing an audio file, the red line that shows were the audio is playing . . . use to go to the right, and the audio would continue to the right along with the red line. 

But now, when the red line gets close to right, it goes off the screen and reappears back at the beginning of the screen along with audio.

Does anyone know how I can change it back to show the screen continuing to the right along with the red line?

Sincerley

Dean H.