Comment 23 for bug 1292290

I've used a xslt to remove al empty properties. It appears to work.

I created a xslt file "remove-empty-properties.xsl" with this content

<xsl:stylesheet xml:space="default" version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" version="1.0" encoding="utf-8" omit-xml-declaration="no" />
  <xsl:template match="node() | @* | text()">
    <xsl:copy>
      <xsl:apply-templates select="node() | @* | text()" />
    </xsl:copy>
  </xsl:template>
  <xsl:template match="property[not(property) and @type='empty']" />
</xsl:stylesheet>

# now, make a backup of your configuration
mv xfce4-keyboard-shortcuts.xml xfce4-keyboard-shortcuts.xml.bak

# after, clean the file with xsltproc. (you can install it with the command "apt-get install xsltproc")
xsltproc -novalid remove-empty-properties.xsl xfce4-keyboard-shortcuts.xml.bak > xfce4-keyboard-shortcuts.xml

It works for me :)