Thank you for your answer Andreas, I was able to make it work again.
I'm trying to configure my ESC key so a long press will put the Mac to sleep, but it's not working.
I created a new action, pressing the ESC key and setting "Trigger on key Down" with "Minimum time key needs to be pressed" set to 1,31 seconds. But nothing happens when I keep the key down.
I also tried with another key (F1) following these instructions:
The short press works, long press not.
I'm (still) using Mojave, on an old 2012 Mac Mini. Could this be the problem?
Thanks.