Why no gradient support for sequence diagram boxes?

Question

When styling a sequence diagram I can use gradients on participants and notes, but not on boxes around some participants. Is there any reason for this?

For example the following fails, but delete the first "/blue" and everything else works!?

@startuml
box BoxOfAlice #yellow/blue
  participant Alice #yellow/blue
end box

Alice -> Bob: Hello

note over Alice #yellow/blue
  fancy!
end note
@enduml

Answer 1

Thanks for the feedback. Gradient support has been added in second hand, so some part may be missing.

This is fixed with last beta http://beta.plantuml.net/plantuml.jar

Tell us if it's not working for you !