Transparent Sequence Groups

Question

I often draw sequence diagrams for use case realizations that uses both boxes (to group participants, e.g. a controller and a database) and groups (to identify parts where there are alternate flows).

Since the groups have opaque background, the color of the boxes are not visible in the grouped portions.

That's fairly OK if the group isn't more than a few messages high, but I often find myself drawing diagrams where most of the messages are within groups an then the boxes sort of disappear.

Would it be possible to have a transparent group?
E.g. with
skinparam SequenceGroupBodyBackgroundColor transparent

Or by defining a certain color as transparent and use that color as background?
E.g with 
skinparam TransparentColor  Azure
skinparam SequenceGroupBodyBackgroundColor  Azure

/MiKe

Answer 1

I don't understand...  the very command you're asking for seems to already exist?  What am I missing?

The following generates a transparent group:

@startuml
skinparam SequenceGroupBodyBackgroundColor transparent
participant D
  box "Internal Service" #LightBlue
  participant A
  participant B
  A -> B
    group test
    B -> D
    end
  end box
B -> D
@enduml

http://www.plantuml.com/plantuml/umla/NO_12i8m38RlVOempxw2R7KWWZUVe7PXbdLfJLFHjpSh7iHB-t_yV_AJleXZgMiqPGcK7RiLhlYeI1vFd6gsQNfRvvTPWQPZYeb1s57HB98O_IJua1q9Z0RWbbxGdKcGoKLTnS_WiOFT9SntiR6YPdvdXZ-soWFi3qq0RBKP18iqj9ipDeaqcVPkbUPhzCfwp0S0

You can also use style to achieve the same:

http://www.plantuml.com/plantuml/umla/NO_FQiGW48VlFiMGdajV88J4vbBehKymDKCgDMCwZcMNPTzzLN88AoY_Zm_dpvWKHVCMJ9_q6cWm08d-Ch6ZsUCgkC7DG3chnBmVsQBxhSpBUmnHG0KvxIZ4slpTrDk_7IMBKU_yZgmm5_KTBz1zi98m1lWY-VUEEdZvzEkFsf3909p_J4zi2q_mEe0zJQQKjA6jPcwHU37jhItD8SR2PU47

Comments

Thanx!

I realised that after I posted question.

Did a real newbie mistake by not searching through previous questions =^)
But now it works perfectly...