Version 4.9.0 of the XMLmind XML Editor (released on April 18, 2011) has a bug which fails to show the various background colors that XLingPaper uses (e.g. for section ids, sectionRefs, example ids, exampleRefs, citations, objects, etc.).
I’m told the bug will be fixed in version 4.9.1 which is slated to come out in June.
In the meantime, if you should wish to use version 4.8.0 of the XMLmind XML Editor (which does show the background colors), then you can go to http://www.xmlmind.com/archive/xmleditor/4.8.0/ and download and install version 4.8.0.
Windows users should get xxe-perso-4_8_0-setup.exe.
Mac users should get xxe-perso-4_8_0.dmg.
Linux users should get xxe-perso-4_8_0.tar.gz.
Before installing this old version, you will need to uninstall your current version of the XMLmind XML Editor.