19.2 Cocoa-specific issues
19.2.1 The break gesture
If a CAPI/Cocoa window is busy and unresponsive you can use the break gesture
Command+Ctrl+, (comma) to regain control.
19.2.2 The Cocoa application interface
You can use set-application-interface on an instance of a subclass of cocoa-default-application-interface to get the following functionality:
Define the application menu (leftmost menu in the menu bar).
Define the menu bar items that are displayed when no interface is on the screen.
Define the Dock context menu, which is raised from the Dock icon.
Control and callbacks about the lifecycle of the interface.
A proper Cocoa application is likely to use this mechanism. Note that the call to set-application-interface needs to happen before any display or attempt to access the screen. See cocoa-default-application-interface for more details.
CAPI User Guide and Reference Manual (Macintosh version) - 3 Aug 2017