Difference between Once and Only Once is unclear

When I use the the USB Key Trigger, there's an option to "is tapped once and "is tapped only once". Does anyone know the difference between those two?

20240624_113421_Keyboard Maestro

There seems to be a thorough answer to this question by the Architect on this thread:

1 Like

Hm, after reading through the entire thread, I still can't find the answer to my question. I understand the difference between Tapped and Tapped Once, but there's also Tapped Only Once. That last one I don't get! :slightly_smiling_face:

As I understand it the tapped only once, twice, etc. variants differs from the tapped once, twice, etc. in that the latter does not wait to check for more taps before triggering, and can therefore trigger immediately when the number of taps are reached. The negative side effect of this reactivity is that if you have different triggers set up for different number of taps of the same key, e.g. A is tapped once, and A is tapped 3 times, it will will also trigger at the first tap while tapping away to reach the 3 tap trigger. The tapped only once will wait to se if there are no more taps, and trigger only if there are noe more taps.

Better exemplified by the macro bellow, than by my explanation above:

Tapped and tapped only triggers.kmmacros (19 KB)

Tap A once and you will se that it triggers first for tapped once, then after a very brief moment it will trigger for the only once. If you tap A three times you will notice it triggers for tapped once before tapped 3 times, but it will not trigger for the only once.

1 Like

You are right. Sorry. I guess the docs expect us to understand based on the words themselves. If we can't get an answer from anyone, we can test it. Here's how we could test it.

First macro:


The difference is that if you press F1 twice, the macro will trigger on the first click. But if you press F2 twice, the macro won't trigger at all. That's the difference.

By the way, it's handy to open the debugger for this, because if you press F1 twice in a row, you will see that it's triggering on the first press of F1, not on the second press.

Thanks, @Alexander and @Airy. This makes total sense and I understand now!