Hi S.
I think the editor used is actually what is configured for
the Windows operating system. For me, mine open in Dreamweaver,
despite the fact Notepad is configured as the editor inside
RoboHelp for .JS files.
Personally, I think it's a bug and you should report to Adobe
via the WishForm. You may do this by
clicking
here and completing the form you should find there.
Cheers... Rick