Hey! I think this is more of an Ableton thing, if I understand your question properly.
In the Simpler’s controls (not the eSimpler) look for a little button/control called Trigger/Gate:
- In Gate mode, it will only play the slice when you hold down the note/key/pad, and stop when you release your finger.
- In Trigger mode, it will play through the entire slice and then go to black (I think this is what you’re looking for)
There’s also a pull-down menu called Playback: in Mono, it will play through the slice as above. In Thru, if you trigger a slice, it will play through the slice and continue playing until the very end of the sample.
The Simpler is awesome, a lot more detail here: Live Instrument Reference — Ableton Reference Manual Version 12 | Ableton
Cheers!