Number types are not sorted correctly

Sorting number types int the table does not work.  This can be reproduced directly with the 0.9.0 version docker image.

docker run -p 8080:8080 --rm --name zeppelin apache/zeppelin:0.9.0

Select demo note: Spark Basic Features,  and switch to the table to sort directly. You can see that the number type are still sorted according to the string type even if I specify the type as number.

Using the same steps works fine in 0.8.1 docker image.

Please confirm whether this is a bug or a problem with my usage.