/**
  * Desactivate this MatchingBlockManager to listen to the KeywordEvent generate by a MouseOver.
  */
 public void desactivateMouseOver() {
   if (mouseover != null) {
     pane.removeKeywordListener(mouseover);
     mouseover = null;
   }
 }
 /** Activate this MatchingBlockManager to listen to the KeywordEvent generate by a MouseOver. */
 public void activateMouseOver() {
   if (mouseover == null) {
     mouseover = new MouseOverMatcher();
   }
   pane.addKeywordListener(mouseover);
 }