Called when the window is about to enter full-screen mode.
- macOS 10.7+
The window to enter full-screen mode.
An array of windows to use for the animation to full-screen mode for
This method lets a window delegate customize the animation when the window is about to enter full-screen mode by providing a custom window or windows containing layers or other effects. If you don’t want to perform custom animation, you can omit the implementation of this method, or it can return