# `GSWindowController windowWillReturnUndoManager:`

*Instance Method*

## Declaration

```swift
@MainActor func windowWillReturnUndoManager(_ window: NSWindow) -> UndoManager?
```

```objc
- (NSUndoManager *) windowWillReturnUndoManager:(NSWindow *) window;
```

```python
windowWillReturnUndoManager_(window: NSWindow) -> NSUndoManager
```