# TrickleDown

> Execute the event handler during the TrickleDown propagation phase if the event tricklesDown and the element is a parent of the event's target, or if the callback is registered directly on the event's target.

## Definition

* **Type:** Field
* **Namespace:** [UnityEngine.UIElements](/engine/7000.0/script-reference/unityengine/uielements.md)
* **Assembly:** UnityEngine.UIElementsModule

```csharp
TrickleDown = 1
```

### Remarks

Handlers that use [TrickleDown.TrickleDown](/engine/7000.0/script-reference/unityengine/uielements/trickledown/trickledown.md) are executed before those that use [TrickleDown.NoTrickleDown](/engine/7000.0/script-reference/unityengine/uielements/trickledown/notrickledown.md).

Additional Resources: [EventBase.tricklesDown](/engine/7000.0/script-reference/unityengine/uielements/eventbase/tricklesdown.md), [PropagationPhase.TrickleDown](/engine/7000.0/script-reference/unityengine/uielements/propagationphase/trickledown.md)