a preview of the new version of JetGroovy plugin is available at http://www.jetbrains.net/confluence/display/GRVY/JetGroovy1.1EAP
A summary of new features:
-Improved resolve and completion in GSP: now JetGroovy knows about implicit variables like params, application and such.
-Grails facet is detected automatically, for example when importing an exisiting grails application.
-Annotations PSI is implemented, as a result JUnit4/TestNG tests can be run from IDEA
-Property files support is extended to understand references from groovy files
-Extract method refactoring
-Inline method refactoring
-Inspection to flag unused assignment
-Inspection to flag possibly uninitialized variable access
-Rename now correctly insert parameter declaration for renaming closure's implicit 'it' parameter
-Surround with closure now preserves code semantics inserting 'owner' qualification when needed
Your feedback is most welcome as usually.
We will publish the new version to confluence once it has undergone enough testing.