##Collapsing boxes
##collapse expand boxes
##You can hide the details of boxes, by using 'collapsed=yes' or 'collapsed=arrow'. The latter turns the content into a block arrow. These are also available from the GUI. The collapsed box will include a small indicator to show hidden content.
a, group [collapsed=yes] {
    b, c, d;
}, e;
a->b: Message;
box b--d: Box {
    b->c->d: Message;
};
d->e: Message;
d<-e: Message \#2;
box group--group: Box {
    b<-c-d: Message \#2;
};
a<-b: Message \#2;
