Can't use 'Type Hierarchy" (Ctrl + H) with version 8.1

Hi everyone,

I've ran into a problem with version 8.1. In version 7x I could use the "Type Hierachy" for Groovy Classes in a Grails project. Seems to be broken in version 8.1 or is there a trick with configuration?

Thanks in advance!

Regards,
Markus