In old version the border style was correct shadowed in following sample, but now the shadow is lost:
@startuml
skinparam rectangle {
shadowing false
}
skinparam rectangle<<webApp>> {
BackgroundColor #438DD5
Shadowing<<webApp>> true
}
rectangle "Web Application" <<webApp>> as web_app
@enduml
Thank you and best regards
Helmut
PS.: My generated entry with double defined <<webApp>> looks strange (I don't know why it was used/required last time) but without second <<...>> it is not working too ( skinparam rectangle<<webApp>> { ... Shadowing true ... )