Click the Precedence tag to examine information about the precedence list of the current class. The precedence view shown in Displaying precedence information in the Class Browser appears.
The precedence list is used to generate the method combinations for a class, and thus can be used to tell you which method applies in a given case.
See The Generic Function Browser for details on examining information about methods.
Figure 8.12 Displaying precedence information in the Class Browser
The areas available are described below.
LispWorks IDE User Guide (Windows version) - 25 Nov 2011