Has anyone seen an editor/IDE that shows WYSIWYG comments inside the code? I have seen some that show the docs of an element in a separated tab/windows, but not together with code. For example, a JavaDoc comment would be much clearer and easier to edit if it had no tags and could be edited like a snippet from a normal text document.

/**
 * Writes <code>Hello world!</code> to the <b>standard output</b>.
 * @seealso showGoodbye
 */
public static void showHello() {

Could be something like this:

/*
Writes Hello world! to the standard output.
See also: showGoodbye()
*/

public static void showHello() {

but, editable, of course.

And for anyone who happens to have some knowledge/experience with open IDEs like Eclipse, Netbeans, etc.: would it be too hard to implement this?