Bitflux Editor
The Bitflux Editor (BXE) is what is known as WYSIWYG editor, whose purpose is to edit XML-, or XHTML-Resources. This editor is available for Resources of type XHTML and can be loaded by selecting the Edit in BXE tab from the context menu. BXE basically has the features of a regular text editor, including some peculiarities for dealing with the markup of your documents.
Editing a xhtml Resource in BXE
An extensive Manual of the BXE can be found at http://docs.bitflux.org/files/bxe-manual.pdf.