A Boolean value that determines whether the button displays its border only when the pointer is over it.
- macOS 10.0+
The value of this property is
true if the button’s border is displayed only when the pointer is over the button and the button is active. The value is
false if the border is displayed all the time, regardless of the position of the pointer. By default, this method returns
false, the border is never displayed, regardless of the value of