Recording virtual MIDI loops loop forever (until end of song) when created?

Every time I finish recording a virtual MIDI loop, it loops until the bar indicating the end of the song. This is extremely inconvenient because I am producing batches of sound effects, not looping music. I think I might have clicked or pressed something to trigger this. I quit Garageband and opened it back up, but that did nothing.

I want to record a loop and have one instance of it, not loops and loops of it. How can I turn this off?