External editor for RTF other than MS Word?
 

UR can handle rich text format files with MS Word shown in Internet Explore.
That's really great.

But since MS word is full-fledged, it's not light weight.

Are there any app which can be executed in IE other than MS office to edit rtf files ?

If any, that could be an attractive alternative to UR's internal editor.

Not that I'm aware of.

Abiword edits .RTF documents, it is a lightweight word processor.

I don't know if it opens in IE or not but it's free and might be worth a try.

Jarte is another option. It does not open in IE, but it is very lightweight.

Jon