private void makeUndoable(JTextComponent textComponent) {
// code from: http://stackoverflow.com/a/12030993
final UndoManager undoManager = new UndoManager();
Document doc = textComponent.getDocument();
doc.addUndoableEditListener(new UndoableEditListener() {
@Override
public void undoableEditHappened(UndoableEditEvent e) {
//System.out.println("Add edit");
undoManager.addEdit(e.getEdit());
}