# `GSLayer.undoManagerCheck`

*Instance Property*

The undo manager of the containing glyph when undo registration is enabled.

## Declaration

```swift
var undoManagerCheck: UndoManager? { get }
```

```objc
@property (nonatomic, readonly) NSUndoManager * undoManagerCheck;
```

```python
undoManagerCheck() -> NSUndoManager
```

## Discussion

Returns `nil` when the layer does not belong to the glyph or undo registration is disabled.

## See Also

### Undo

- [`GSLayer.undoManager`](/Core/GlyphsCore/GSLayer/undoManager) — The undo manager of the containing glyph when the layer belongs to that glyph.