1. click on Register server window and Go to Filter tab
2. Go to object folder and create new filter on user defined datatypes with primary and secondary filter.
3. save the connection and Go to Datatypes tree node
4. we can see that filter is not applied on Datatypes
5. There is the Datatype tree node so in the folder filter drop down list "user defined datatypes" should be named as "datatype" and it should be worked for filter datatypes.
Works fine for me. See attached screenshot. I will ask Ivan to rename to Datatypes.