private void validatePluginID(Element element, Attr attr, boolean isFragment) {
   String id = attr.getValue();
   if (!validatePluginID(element, attr)) {
     return;
   }
   int severity = CompilerFlags.getFlag(fProject, CompilerFlags.F_UNRESOLVED_PLUGINS);
   if (severity != CompilerFlags.IGNORE) {
     IMonitorModelBase model = MonitorRegistry.findModel(id);
     if (model == null
         || !model.isEnabled()
         || (isFragment && !model.isFragmentModel())
         || (!isFragment && model.isFragmentModel())) {
       report(
           NLS.bind(MDECoreMessages.Builders_Feature_reference, id),
           getLine(element, attr.getName()),
           severity,
           MDEMarkerFactory.CAT_OTHER);
     }
   }
 }