Just a note. I had the exact same problem. I needed a kind of “fire button” to allow manual timing of a very short or longer activation of an action.
The trick even non ideal working for me was to add a icon to the button and connect a controller to the icon and then I was able to get the pressed/released signal via the icon.
Downside is you have to click on the icon. If you miss out and hit the edge of the button only the button gets the click.
So it’s a little a hack to save my world without redesigning the nice button appearance.
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