For your convenience.
Downloadlinks are at the end of the article.
Rix's patch for properly using schemas with a target namespace
providing a text_replace.png file (which was missing and, since I am so proud of my Gimp-artwork, I included it in the menu as well)
updating UpdateChildViews in MasterViews.cs, removing the (unnecessary?) this.AddTreeNode(document) and the enclosing foreach loop - now nodes in the left area are no longer duplicated
providing support for Deutsche Umlaute (like ö, ü, ä) and ß - hope it didn't break anything else, anyhow, this is easy to change: it is in file DocumentService.cs, I added System.Text.Encoding.Default to the Load method
(Since active development here seems to kind of have died down, I host it myself - please do with the code what you want, it is the same license as the original here.)