# foldoutOverride

> Register a callback to this property to override the Foldout button in the TreeView.

## Definition

* **Type:** Property
* **Namespace:** [UnityEditor.IMGUI.Controls](/engine/6000.3/script-reference/unityeditor/imgui/controls.md)
* **Assembly:** UnityEditor

```csharp
protected TreeView<TIdentifier>.DoFoldoutCallback foldoutOverride { get; set; }
```