Only Undo/Redo Editing but No Syntax Highlighting

Question

I have a JTextPane with styled content, when I apply undo/redo I don't want the different Color Highlighting to be added to Undo/Redo queue of UndoManager. How can I? My Undo Listener and Actions looks like below:
protected class RulesUndoableEditListener implements UndoableEditListener {
          RuleExpressionUndo undoAction;
          RedoRuleExpression redoAction;
          UndoManager undoMgr;
          public RulesUndoableEditListener(RuleExpressionUndo undoAction,
                    RedoRuleExpression redoAction, UndoManager undoMgr)
               this.undoAction = undoAction;
               this.redoAction = redoAction;
               this.undoMgr = undoMgr;
          public void undoableEditHappened(UndoableEditEvent e) {
                    undoMgr.addEdit(e.getEdit());
                    undoAction.updateUndoState();
                    redoAction.updateRedoState();
class RuleExpressionUndo extends AbstractAction {
          RedoRuleExpression redoAction;
          UndoManager undo;
        public RuleExpressionUndo(UndoManager undo) {
            super("Undo");
            this.undo = undo;
            setEnabled(false);
        public void actionPerformed(ActionEvent e) {
            try {
                undo.undo();
            } catch (CannotUndoException ex) {
                System.out.println("Unable to undo: " + ex);
                ex.printStackTrace();
            updateUndoState();
            redoAction.updateRedoState();
        protected void updateUndoState() {
            if (undo.canUndo()) {
                setEnabled(true);
                putValue(Action.NAME, undo.getUndoPresentationName());
            } else {
                setEnabled(false);
                putValue(Action.NAME, "Undo");
           * @param redoAction the redoAction to set
          public void setRedoAction(RedoRuleExpression redoAction)
               this.redoAction = redoAction;
    class RedoRuleExpression extends AbstractAction {
         RuleExpressionUndo undoAction;
         UndoManager undo;
        public RedoRuleExpression(UndoManager undo) {
            super("Redo");
            this.undo = undo;
            setEnabled(false);
        public void actionPerformed(ActionEvent e) {
            try {
                undo.redo();
            } catch (CannotRedoException ex) {
                System.out.println("Unable to redo: " + ex);
                ex.printStackTrace();
            updateRedoState();
            undoAction.updateUndoState();
        protected void updateRedoState() {
            if (undo.canRedo()) {
                setEnabled(true);
                putValue(Action.NAME, undo.getRedoPresentationName());
            } else {
                setEnabled(false);
                putValue(Action.NAME, "Redo");
           * @param undoAction the undoAction to set
          public void setUndoAction(RuleExpressionUndo undoAction)
               this.undoAction = undoAction;
    }

Answer 1

I believe that in the undoableEditHappened() method you can add code like thefollowing:
AbstractDocument.DefaultDocumentEvent event =
     (AbstractDocument.DefaultDocumentEvent)e.getEdit();
if  (event.getType().equals(DocumentEvent.EventType.CHANGE))
     // attribute change  - do nothing
else
     undoMgr.addEdit(e.getEdit());
     undoAction.updateUndoState();
     redoAction.updateRedoState();
}