How to put a note over several participants in sequence diagrams ?

Question

The following syntax does not work :

@startuml
participant Alice
participant Bob
participant Titi
note over Bob, Alice, Titi
   This is yet another
   example of
   a long note.
end note
@enduml

Answer 1

Instead of using : note over Bob, Alice, Titi

You can use :  note over Alice, Titi

The note will be put over all participants between Alice and Titi:

@startuml
participant Alice
participant Bob
participant Titi
note over Alice, Titi
   This is yet another
   example of
   a long note.
end note
@enduml