I was trying to work out what BiddableBackgroundColor & BiddableBorderColor are for. And I discovered the (undocumented?) Problem Diagram from https://github.com/plantuml/plantuml/pull/120. This seems to implement the concept presented in http://users.mct.open.ac.uk/mj665/SoSyMHJR.pdf
So I gave it a go:
@startuml
title Problem Diagram R1
skinparam BiddableBackgroundColor LightBlue
skinparam BiddableBorderColor red
requirement "Collect and display drone flight paths on a map" as R1
domain "Google Map" as D1 <<Designed>>
domain "Onboard LiveBox" as D2 <<Designed>>
domain "Drone" as D3 <<Biddable>>
domain "Path" as D4 <<Lexical>>
domain "Map" as D5 <<Causal>>
domain "Monitor" as M <<Machine>>
M -- D1: a1
M -- D2: b1
D1 -- D4: d1
D4 <-[dashed]- R1: d
D2 -- D3: e1
D3 -[dashed]- R1: e
D2 -- D4: d2
D5 <-[dashed]- R1: c
D1 -- D5: c1
@enduml
But the Biddable skinparams don't seem to have any effect on the biddable component, please clarify what they are used for.
