Although unconventional in UML diagrams, I could take advantage of the software interpreting a slash n.
In my example, it would be Module\nSomeSuperClass\nConcreteClass. This would save space so the sequence diagram doesn’t get elongated in landscape.
Sounds like an interesting idea. I bet the PlantUML.com folks would like to hear about this. I am not involved in the syntax for PlantUML unfortunately. Try them out at …