On Disappear is related to the visibility of a layer. Just as the name suggests, On Disappear is triggered when a layer disappears from the screen. It is useful for:
Tracking analytics
Triggering an action after a layer disappears
Cleaning up resources or saving data when a layer is no longer visible (ie. stopping an animation or saving user input when a layer is dismissed)
The exact moment that On Disappear is called depends on the specific layer type that you apply it to, but the Actions parameter doesn’t execute until the layer disappears from the interface.
To add an Action, click on the plus (+) icon in the Actions section and click on “Dismiss” to select an action. It’s most frequently used with the Custom code integration.
