[remove @unlinked] IllegalStateException if some groups are empty

Question

Thanks again for the remove @unlinked  feature. It works great.

Testing it, I figured out a few (non blocking) edge cases I put here to help the follow-up :

IllegalStateException if some groups are empty :

@startuml

together t{

}

remove @unlinked

@enduml

Comments

This case seems not be fully corrected, see this simple example:

@startuml
together {
}
remove @unlinked
@enduml

→ http://www.plantuml.com/plantuml/uml/SoWkIImgAStDuIh9JqyjoKWjKgZcgkKgIitDBqjLS2ZDoydCoqvDuN98pKi1gW80