How do I stop the Oscillator Mode from continuing to play once a sample has ended?

I have a short audio wave, say .4s long, and I use an Oscillator on it to modify the sound. However, when the note ends; either the sample ends or even if the timeline finishes, the oscillator continues to make a tone afterward. I can't figure out how to make it stop!

My ADSR envelopes look sensible. I've tried cutting them short to no avail. I am at a loss :(

*edit* Ah ok, if I set it to Sustain instead of Play mode, that fixed it. It was very confusing, though; I guess the Oscillator invisibly adds time to the end of the sound.