Empty array in "required" field in Schema Object

According to OpenApi3 (actually, Json Schema) specification empty array is allowed for "required" field in Schema Object. (see https://github.com/json-schema-org/json-schema-spec/issues/69)
But swagger-editor tool throws errors like "....required should NOT have less than 1 items" and in the website 

https://swagger.io/docs/specification/data-models/data-types/ written the same.
Is this a bug in the web-site documentation and in the swagger-editor tool?