A number of operations can be performed on functions selected in the Text area (when in the Text view) or in the Called By or Calls Into areas, or on the current function (when there are no functions selected elsewhere).
The Function menu gives you access to the standard actions described in Performing operations on selected objects.
The Function > Trace submenu gives you the ability to trace and untrace the functions selected in the Text , Called By and Calls Into views.
LispWorks IDE User Guide (Macintosh version) - 25 Nov 2011