I didn’t see this feature in your line up (otherwise very nice). But at some point after you finalize your UML development you may seriously want to consider adding this feature to your XML line up. In short it helps the coder to read and edit the XML docs and schema’s Good examples of this would be:
1) XML Marker 1.1 (freeware) can be found on Downloads.com, tucows etc. Screen shot available at http://www.download.com/3000-7241-10202366.html (but there is more to it then shown in the screen shot).
2) A plugin for Eclipse called XML Viewer (http://www.exchangerxml.com/editor/features.html). Decent screen shots for examples.