When the Frames and Arguments preference has the value Two list-panels , the Debugger appears as shown in below.
Figure 11.3 Debugger tool with two list-panels
Each item in the Backtrace: list represents a stack frame associated with a function call. You can operate on the frame as described in Backtrace area.
A second list titled Local variables: shows the local variables of the frame which si selectd in the Backtrace: list. You can operate on the variables similarly to the backtrace tree: double click on a variable to inspect it or use the commands in the Debug > Variables menu, which is also available as the context menu.
Note: with Two list-panels , only the local variables of the current frame are displayed.
LispWorks IDE User Guide (Windows version) - 25 Nov 2011