@Override
      public boolean isAcceptable(Object _element, PsiElement context) {
        PsiElement element = (PsiElement)_element;
        PsiFile file = element.getContainingFile();

        return (HtmlUtil.hasHtml(file) || HtmlUtil.supportsXmlTypedHandlers(file)) &&
               isAcceptableAttributeValue(element);
      }
@Override
      public boolean isAcceptable(Object _element, PsiElement context)