# GH_RibbonLayoutEditor.UndoRedoChangedEventHandler delegate

Namespace: [Grasshopper.GUI](https://developer.rhino3d.com/api/gh1/namespace/grasshopper.gui.md) · Assembly: [Grasshopper](https://developer.rhino3d.com/api/gh1/assembly/grasshopper.md)

```cs
public delegate GH_RibbonLayoutEditor.UndoRedoChangedEventHandler
```

**Signature:**

```cs
void GH_RibbonLayoutEditor.UndoRedoChangedEventHandler(object sender, GH_RibbonLayoutEditorUndoRedoEventArgs e)
```

**Parameters:**

- `sender` ([object](https://learn.microsoft.com/dotnet/api/system.object))
- `e` ([GH_RibbonLayoutEditorUndoRedoEventArgs](https://developer.rhino3d.com/api/gh1/type/grasshopper.gui.gh-ribbonlayouteditorundoredoeventargs.md))