I still don't get it.
If I produce XML and define my own DTD and related tags, isn't that "custom XML"? I don't need an XML editor specifically to write XML just as I don't need an HTML editor to write HTML, although it helps.
The fact that you can edit XML (or HTML) in Word shouldn't violate anyone's patent (or the patent should never have been issued) with the possible exception if Microsoft stole this company's code to implement the feature.
If what they were trying to protect was this metadata map, isn't that nothing more than indexing the location to all the tags? That's no big deal either and unless it's a stupendously big file, also unncecessary, because normal indexing and search will find the tags.
What am I missing? (In English, please.)
And when people file stupid lawsuits against Microsoft, we should be just as outraged as when people file stupid lawsuits against Apple. It's well known that the patent system is completely broken. Ideas were never supposed to be patentable, only the specific implementation of those ideas--Amazon's One-Click being an example of something that should never have received a patent. Same for copyrights. You can't copyright a "Western", you can only copyright your particular telling of a Western story.