@Override
  public boolean isAcceptable(Object element, PsiElement scope){
    if (!(element instanceof XmlDocument)) return false;
    final XmlTag rootTag = ((XmlDocument)element).getRootTag();
    if(rootTag == null) return false;

    return getFilter().isAcceptable(rootTag, (PsiElement)element);
  }
@Override
  public boolean isAcceptable(Object element, PsiElement scope)