private void jumpTo(final String ref){
  if (ref.isEmpty()) {
    textPane.scrollRectToVisible(new Rectangle(0,0,1,1));
  }
 else {
    textPane.scrollToReference(ref);
  }
  currentReference=ref;
}

private void jumpTo ( final String ref ) { if ( ref . isEmpty ( ) ) { textPane . scrollRectToVisible ( new Rectangle ( 0 , 0 , 1 , 1 ) ) ; } else { textPane . scrollToReference ( ref ) ; } currentReference = ref ; }
jump to the given position ( ref ) in the current page
