@Override
 public void onComponentSelection() {
   LinkerSelectionContext lh = linker.getSelectionContext();
   if (lh.getSingleSelection() != null) {
     String locale = JahiaGWTParameters.getUILanguage();
     new CompareEngine(lh.getSingleSelection(), locale, linker, true, false).show();
   }
 }
 @Override
 public void handleNewLinkerSelection() {
   LinkerSelectionContext lh = linker.getSelectionContext();
   setEnabled(lh.getSingleSelection() != null);
 }