How to prevent the selection marker from moving?

How do I force the selection marker to stay where I place it so that playback starts from that point again after it reaches the end of the track? Using headphones, I was trying to find the point where the track fades to silence with the volume turned all the way up. I'm used to Cool Edit Pro, and I didn't notice that the selection marker was moved without me doing it. When I pressed play a second time, playback started at a very high volume at the beginning of the track. My ears are still hurting and ringing badly 25 minutes later. I need to turn the volume up to figure out where to trim the track. How do I prevent the selection marker from moving and playback from jumping to a loud section?