IntelliJ IDEA 

- Create new project.
- Import from Grails sources.
- Overwrite .idea -> yes (should not destroy runConfigurations).
- Don't commit any other IDEA project files (they can all be generated).

#### runConfigurations.
The "module" is set to a path variable "$grailsAppModuleName$".
Set the value in IDEA settings not in runConfigurations dialogue.
Once the path variable is set, change it with all projects closed when switching branches.

Do not commit changes to "$grailsAppModuleName$".
If accidentally changed with the runConfigurations dialogue then please revert.