You can also view code in free external editors like NotePad++ and PSPad, which will even have keyword colouring if you have the Progress syntax plugin for them.
It's been pointed out to me offline the NotePad++ extension is hard to get hold of.
I've never actually installed it (only the PSPad one), but I have read about it in a couple of places, though the OEHive reference appears to have been removed.
Download details (but I can't download it at the moment):
http://yuvcom.com/progress4gl/index.html
developer email details available here:
http://www.progresstalk.com/showthread.php?t=111757
which was robo-nicked from OEHive.
It's worth noting that according to the first page linked to above,
the Notepad++ extension overwrites executable files, rather than supplying a simple syntax text file (as with PSPad), presumably because that's the only way it can be done.
This introduces security, functionality and possibly license considerations, particularly wrt to corporate policy - no slur on the developer's integrity implied (community efforts appreciated here), you just need to be aware of that.