CLIM supplies a set of gadgets that have been designed to be compatible with a variety of user interface toolkits, including Xt widget-based toolkits (such as Motif), OpenLook, and the MacToolbox.
Each gadget maps to an implementation-specific object that is managed by the underlying toolkit. For example, when a CLIM program manipulates an object of class scroll-bar , the underlying implementation-specific object might be a Motif ScrollBar widget. As events are processed on the underlying object, the corresponding generic operations are applied to the Lisp gadget.
Note that not all operations will necessarily be generated by particular toolkit implementations. For example, a user interface toolkit that is designed for a 3-button mouse may generate significantly more gadget events than one designed for a 1-button mouse.
Common Lisp Interface Manager 2.0 User's Guide - 7 Aug 2017