principalItemIdentifier
The identifier of an item you want the system to center in the Touch Bar.
Declaration
var principalItemIdentifier: NSTouchBarItem.Identifier? { get set }Discussion
The system attempts to center a principal item within the Touch Bar. If you want a group of items to appear centered in the Touch Bar, designate the group item (of type NSGroupTouchBarItem) as the principal item.
If more than one bar in the responder chain is eligible to be visible in the Touch Bar, and more than one of those has a principal item, the system determines which one to center in the Touch Bar.
The system archives this property.