The backtrace list displays the function calls on the debugger stack. Each item, referred to as a frame on the stack, shows a separate function call.
Selecting any frame displays any variables associated with that function in the Variables area.
Double-clicking on any frame finds and displays the source code definition for that function in the editor, prompting you for a tags file first, if necessary.
Any item selected in this area can be operated on using the commands in the Frame menu: See Performing operations on frames in the stack for details.
Starting with version 4.2 of LispWorks, the backtrace list is a tree control: opening a node in the tree (which corresponds to a specific stack frame) provides detailed information of variables defined in the selected stack frame. You can double click on any variable to inspect the variable using the inspector tool. Any items selected in this area can be operated on using the commands in the Variables menu: see Performing operations on variables in a frame for details.