rule Classes2Drop {
	from
		s: UML2!Class (
			 s.getAppliedStereotypes().isEmpty()
		)
	to
		drop
		
}

The object 'org.eclipse.uml2.uml.internal.impl.ClassImpl@110b4ae (name: CreateNewIncidentActionDelegate, visibility: <unset>) (isLeaf: false, isAbstract: false, isFinalSpecialization: false) (isActive: false)' is not contained in a resource.

rule Classes2Drop {
	from
		s: UML2!Class (
			 s.getAppliedStereotype('profile::Perspective').oclIsUndefined()
		)
	to
		drop
		
}

Hi everybody,
I recently started using the refining mode on ATL, I write -- @atlcompiler atl2010 at the start of the compiler, and all my rules right now seemed to work ok.

Then I tried to use the 'drop' feature as follows:

rule Classes2Drop {
	from
		s: UML2!Class (
			 s.getAppliedStereotypes().isEmpty()
		)
	to
		drop
		
}

And there seems to be some kind of error that I don't understand at all, it just says:
Quote:

The object 'org.eclipse.uml2.uml.internal.impl.ClassImpl@110b4ae (name: CreateNewIncidentActionDelegate, visibility: <unset>) (isLeaf: false, isAbstract: false, isFinalSpecialization: false) (isActive: false)' is not contained in a resource.

So I wondered why this happened and I came up with several questions:
1 - do all the elements contained in these classes get deleted too?

2 - What happenes to the elements that reference these classes, or any other dropped element? is that what causes this error?

3 - what else could be the cause for this error?

I know it says that that element is not contained in a resource, but that doesn't seem to be the cased, also it seems to be an element of the type class, I don't get it.

If I change the code to address a certain stereotype like this:

rule Classes2Drop {
	from
		s: UML2!Class (
			 s.getAppliedStereotype('profile::Perspective').oclIsUndefined()
		)
	to
		drop
		
}

I get exactly the same error.
I didn't find much information online, so I'm completely lost here, I hope you guys can help!

Regards,
Javier