Grails / Groovy / GGTS: Conflicting module versions on run-app

Question

After upgrading a Grails application from 2.2.0 to 2.2.1 I keep getting the following error when attempting to debug a Grails application from GGTS via Debug as... -> Grails

Answer 1

Currently (using Eclipse 2020-06, 4.16.0) none of the above solutions work any more.

1. Open the Run Configuration of your groovy script
2. Remove all User Entries from the Classpath tab
3. Press "Restore Default Entries"

This should add the default classpath containing your specified Groovy version as User Entry.