At the top of the debugger tool is a row of buttons, as described below. Press:
If you hold the mouse cursor stationary over any button for about one second, then help text appears that identifies the button.
to break the current execution.
to return from the debugger and invoke the continue restart.
to return from the debugger and invoke the abort restart.
to select the previous stack frame in the backtrace area.
to select the next stack frame in the backtrace area.
to print the backtrace in the Listener.
to print the variable bindings of the current frame in the Listener.
to find the source code for the current stack frame.