Looping Room Tone

As an audiobook narrator still new to Pro-Tools, I frequently copy paste room tone over mouth clicks and other funky noises, but when I play back, the copy pasted area keeps looping over and over itself, until I click all over the place and it stops. Terrible waste of time.

I haven't been able to figure out what sequence of clicks makes it stop, but I suspect there's a setting somewhere that I can change...so when I play back, the cursor just keeps on moving through both sides of the copy pasted section.

Help? Thanks...