I was excited to discover the subgraph feature, thinking I could create interactive diagrams using clicks or double-clicks to expand and collapse areas of it. I saw it as a way to zoom around a complex diagram while working on it or as a presentation tool; Click a shape and SHAZAM it explodes into more shapes! Click again and they go poof!
But alas… That’s not how it works.
So what DO people do with subgraphs? It is an intriguing function…
It is a way to group items together and “collapse” these so that they are visually less intrusive. It provides a bit of drill-down capability for a complex diagram. With two or more elements selected, select group as subgraph. Right click the new subgraph and select collapse, this shows a small “subgraph” in the area where you had some complex drawing going on before.
The way one interacts with subgraphs through the right click menu is frustratingly uncool/slow. As a result I never use them.