Retrieving AttributeSet from PlainDocument

Question

In looking at the composition of javax.swing.text.Element and the Document and AttributeSet interfaces - it appears as if I should be able to retrieve an AttributeSet that was assigned to a particular location when a string is inserted into a Document.
However, the code snippet I tried does not return the AttributeSet I sent into the document with insertString. I tried this with both a PlainDocument (usint a JEditorPane) and a DefaultStyledDocument (using JTextPane).
Is my understanding incorrect? If I do an insertString against a document - supplying an AttributeSet (contents different from items on other side) - shouldn't I be able to get the AttributeSet back by retrieving the element at that offset?
Code snippet attached,
jgr
Document doc = jEditorPane.getDocument();
String tag = "TAG";
SimpleAttributeSet attrs = new SimpleAttributeSet();
attrs.addAttribute(tag,"a test tag");
int insertLocation = 0;
doc.insertString(insertLocation, "ABCD", attrs);
int index = doc.getDefaultRootElement().getElementIndex(insertLocation);
Element element = doc.getDefaultRootElement().getElement(index);
AttributeSet eAttrs = element.getAttributes();
// I thought this would display "a test tag" - but it doesn't.
// it returns null.
System.out.println(" entry contents=" + eAttrs.getAttribute(tag));

Answer 1

AttributeSet eAttrs = element.getAttributes();I think this set should be a Java runtime implementation of one of four predefined attribute sets
which are, by definition, immutable.