[Feature Request] Repeat actors in sequence diagrams

[jimpudar]

I make a lot of large sequence diagrams with multiple sections, and when you scroll down far enough you can no longer see the actors at the top anymore.

I would like to be able to repeat the actors at any point in the diagram, e.g. between grouped sections, or at the bottom.

[bo-ku-ra]

i want to look like this.
however, horizontal interlocking scrolling is necessary and difficult.
sample.zip