XF Designer supported documents

Q1: Can I edit standard XSL-FO documents in XF Designer using the Design View?
A1: Yes, you can edit standard XSL-FO documents in XF Designer, in both the Design View and the Text View.
XSL-FO documents begin with the fo:root tag:

<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">

Q2: Can I edit standard XSLT documents in XF Designer using the Design View?
A2: No, XSLT was designed to be edited in text mode. Many fundamental XSLT elements like xsl:template, xsl:apply-templates, xsl:variable, etc have no visual representation in a wordprocessing document template. Standard XSLT can only be edited in Text View.
XSLT documents begin with the xsl:stylesheet tag:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

Q3: What is XFD and why should I use it?
A3: XFD is a format developed by Ecrion with the goal of eliminating the complexity of XSLT and making it appropriate for visual editing. XFD can be edited using either Design View or Text View. An XFD document is converted to standard XSLT at runtime.
XFD documents begin with the xfd:document tag:

<xfd:document xmlns:xfd="http://www.ecrion.com/xfd/1.0">

Q4: Can I convert my XFD templates to XSLT and back?
A4: The option of generating the equivalent XSLT is available at any point during editing, however standard XSLT cannot be converted back to XFD for the reasons mentioned in Q2.