泳道分组并且着色

分组用 box和endbox ，颜色用#xxx，标注用"xxx"

box "浏览器" #LightGreen
participant "浏览器1" as Browser
participant "浏览器2" as Browser2
endboxparticipant "服务端" as Server #orange

未修改前：

修改后：

效果：可见图中浏览器1和浏览器2放到了一起，并且叫浏览器的title

@startumlautonumberactor "用户" as Userbox "浏览器" #LightGreen
participant "浏览器1" as Browser
participant "浏览器2" as Browser2
endboxparticipant "服务端" as Server #orangeactivate UserUser -> Browser: 输入 URL
activate BrowserBrowser -> Server: 请求服务器
activate ServerServer -> Server: 模板渲染
note right of Server: 这是一个注释Server -> Browser: 返回 HTML
deactivate ServerBrowser --> User@enduml