Every control has a set of events that it raises in response to specific user actions or system occurrences. The list of a control's events appears on the Events tab in the Properties view when the control is selected in the Visual Designer.

To make your application respond to a given UI event, such as a button click, your ABL code must both subscribe to the event and define the desired response. Simply double-clicking an event in the Properties view automatically generates an event subscription and an event method in which you can define the appropriate logic.