Hi Jon,
The "Discard OK Results" option discards the actual contents of a TestStep Result (for example the request/response messages) if the step passed ok, but still shows/keeps the TestStep Result in the log. The "Discard Removed" option removes TestStep results rolled out from the log from memory alltogether (the previous option does not do this); you can safely check this if you are not accessing results or want to create reports after the run of your TestCase. Finally, the "Follow" setting should automatically always highlight/scroll the last result into view.
regards!
/Ole
eviware.com