# `GlyphsToolbarExtensionProvider toolbarExtensionForWindow:`

*Instance Method*

Called before the toolbar is added to the window.

## Declaration

```swift
func toolbarExtension(for window: NSWindow) -> (any GlyphsToolbarExtension & NSObjectProtocol)?
```

```objc
- (NSObject<GlyphsToolbarExtension> *) toolbarExtensionForWindow:(NSWindow *) window;
```

```python
toolbarExtensionForWindow_(window: NSWindow) -> NSObject<GlyphsToolbarExtension>
```