The bar that is displayed when a user press-and-holds on the popover item.
- macOS 10.12.1+
- Mac Catalyst 13.0+
NSTouchBar can be the same as the one used for the
popoverTouchBar property, but does not have to be.
nil this touch bar is displayed while the user holds their finger down on the collapsed representation of the popover item. When the user raises their finger, this bar disappears.
Configuring the Expanded Popover