Added 'NamedConstant' drag'n'drop in text programs as well (was only accepted on graphical languages).
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Python xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.w3.org/2001/XMLSchema" xsi:schemaLocation="python_xsd.xsd">
<![CDATA[]]>
</Python>