@Override
    public boolean isReferenceTo(@NotNull PsiElement element) {
      if (element instanceof SchemaPrefix && element.getContainingFile() == myElement.getContainingFile()) {
        final PsiElement e = resolve();
        if (e instanceof SchemaPrefix) {
          final String s = ((SchemaPrefix)e).getName();
          return s != null && s.equals(((SchemaPrefix)element).getName());
        }
      }
      return super.isReferenceTo(element);
    }
@Override
    public boolean isReferenceTo(@NotNull PsiElement element)