-// Handle a parameter with a series of string arguments, to be added to a comma-delimited
-// list. Passes each token through the CleanUpPathNameSlashes() function to ensure
-// consistency in subsequent comparisons of filenames.
+// Handle a parameter with a series of string arguments, to replace or be added to a
+// comma-delimited list. Passes each token through the CleanUpPathNameSlashes() function
+// to ensure consistency in subsequent comparisons of filenames. If the first
+// non-keyword token is "+", the list is added to the existing target string; otherwise,
+// the tokens replace the current string.