I guess I got spoiled with XP. I'm a developer working on programs that generate XML files, most of which utilize external entity references.
On my old XP machine, I could just double-click on the xml file and see the full document with the included externals, and be able to expand and contract...
developer tools
documentrenderingdocument viewer
entity references
external references
file association
ie8
javascript
msxml
notepad
rendering issues
software upgrade
tag expansion
third-party software
user experience
windows 7
windows xp
xml notepad
xml viewer