NSMenuToolbarItem
A control that presents a menu in a window’s toolbar.
Declaration
class NSMenuToolbarItemOverview
If you set an action on an NSMenuToolbarItem control item, the user invokes the action when clicking on the item through pressing and holding to display the menu. If you set an action on the item and showsIndicator to true, the system displays the indicator as a separate segment so the user can invoke the menu with a click on that segment.
If you don’t set an action on the NSMenuToolbarItem, a simple click invokes the menu, and the indicator is purely decorative.