A Boolean value that indicates if the pop-up button links the state of the selected menu item to the current selection.
- macOS 10.0+
When the value of this property is
YES (which is the default value), the state of the selected item is set to
NSOn. When the value of this property is
NO, the items in the menu are left alone. When you change the value of this property, the state of the currently selected item is updated appropriately.
Note that this property affects only pop-up buttons (it is ignored for pull-down menus).