A call to the define-application-frame macro creates a subclass of the standard-application-frame class. CLIM application frames are instances of these generated subclasses. You explicitly specify accessors for the slots you have designated for storing application-specific state information. The use of the accessors is as for any other CLOS instance. Other CLIM defined components of standard-application-frame subclass instances are accessed via documented functions. Such components include frame-panes, command-tables, the top-level window, and layouts.
CLIM 2.0 User Guide - 01 Dec 2021 19:38:58