The shadow displayed underneath the view.
- macOS 10.5+
The default value of this property is normally
nil. When you configure any of the shadow-related properties on the view’s layer, such as the
shadow properties, this property contains the
NSShadow object that encapsulates that information. Assigning a new shadow object to this property sets the corresponding shadow-related properties on the view’s layer.
If the view does not have a layer, setting the value of this property has no effect.