Entity documentation has no value for entities declared with SYSTEM OR PUBLIC

[xorye]

With this XML

<?xml version="1.0" standalone="no" ?>
<!DOCTYPE copyright [
  <!ELEMENT copyright (#PCDATA)>
  <!ENTITY c SYSTEM "http://www.xmlwriter.net/copyright.xml">
]>
<copyright>&c;</copyright>

The hover does not show the value of c:

The same thing happens if we have
<!ENTITY c PUBLIC "http://www.xmlwriter.net/copyright.xml">
instead of
<!ENTITY c SYSTEM "http://www.xmlwriter.net/copyright.xml">

It would be great if the entity's value ("http://www.xmlwriter.net/copyright.xml" in this case) was displayed in the documentation.