For the SpringSource Groovy & Grails course I've created several Grails projects as part of the labs. When these labs are imported in a new workspace (by the workspace builder plugin that Christian created, but I don't think that's relevant in this case) none of the Grails projects show a Grails Classpath Container, even though it's specified in the .classpath files. BTW, the workspace auto-configures a Grails 1.3.5 installation from a sibling directory of the STS install dir: I'm not sure if that happens before or after the projects are imported and if that might be part of the problem.
I can fix this problem by doing a Grails Tools -> Refresh Dependencies for each project: after that, the Grails Classpath Container shows up with all of the expected dependencies. However, the projects will still have compilation errors stating that GroovyObject is not on the classpath, even though it is (the groovy jar is contained in the Grails Classpath Container). Cleaning the projects, doing a fake edit or closing and opening the projects doesn't seem to solve this issue: I have to restart the workspace to get rid of these errors. After that everything looks good.
So basically there are two issues, the missing classpath container and the compilation error after the container has been added. I don't know if they are related; the latter issue might even be a GRECLIPSE issue, but I'm reporting it here for now.
If this issue is not related to the workspace builder plugin, would it be an option to automatically run the Refresh Dependencies task for newly imported Grails projects? Right now the workspace is full of errors and requires a lot of manual fixing to become error-free.
I've attached the labs which will hopefully allow you to reproduce the issue.