This is the v24.x UiPath.Form.Activities.
Add a button, create a trigger from it, and you see “your button clicked” as one of the available events for that form. If you edit the Event property of the button, you still see it as “your button clicked” in the Form Trigger activity. After a while I realized the Event setting for the button just issues that event within the form so you can use it to trigger other things. But that Event setting is not what is used by the Form Trigger activity.
It would be great if the two things were linked. The button’s Event setting should be used as an event within the form AND for the Form Trigger. If the value is not filled in, the default event would still be the button clicked…which should function within the form and for the Form Trigger activity.