RE: Syntax-directed XML editor that supports Relax NG sought

 
> Is there a syntax-directed editor, like Epic or XMetal or 
> even Checkmark,
> that supports Relax NG?
> 
> That is, one that will not let invalid markup be entered into 
> a document in
> the first place? 
> 
> If not, why not?

Probably because there doesn't (yet?) appear to be a market worth servicing
for the companies selling these editors.

- Alex.