is this just a extra safety check or can we get into a situation where currentStart < 0 or > numMatches?  Seems like it shouldn't be a case that we need to check but if it's a valid case then shouldn't we do something besides just return?  I remember early versions of  the find in files panel would be blank but there would be 1 result that you couldn't see.  Just trying to understand if you ran into a case where this happened with this code and this check is trying to prevent that.