@Nullable
  private static XmlFile getXsltFile(ConfigurationContext context) {
    final XmlFile file = PsiTreeUtil.getParentOfType(context.getPsiLocation(), XmlFile.class, false);
    if (file != null && file.isPhysical() && XsltSupport.isXsltFile(file)) {
      return file;
    }
    return null;
  }
@Nullable
  private static XmlFile getXsltFile(ConfigurationContext context)