Check out AutoEditNC 3.0--NC Code Editor

<A HREF="http://www.teleport.com/~mattsonm/autonc.htm">Click here:
AutoEditNC 3.0--NC Code Editor</A> ,
http://www.teleport.com/~mattsonm/autonc.htm

The first posting was for the download, sorry.
The one above is for the site where you can see it.
I have opened it and it looks good for a G Code editor, it is a work in
progress, so there will be changes.
bill