Oxygen XML Author Eclipse plugin allows you to edit processing instructions, comments, and CDATA by using CSS extensions.
Example: Editing an Attribute from a Processing Instruction
<?pi_target attr="val"?>@namespace oxy "http://www.oxygenxml.com/extensions/author";
oxy|processing-instruction:before {
display:inline;
content:
"EDIT attribute: " oxy_textfield(edit, '@attr', columns, 15);
visibility:visible;
}
oxy|processing-instruction{
visibility:-oxy-collapse-text;
}