Compound graphs are not supported

[jimon]

I found some older remarks regarding this, but think will create a bug report for future record:

\begin{dot2tex}[dot]
digraph G {
	compound=true;

	subgraph cluster_one {
		a;
	}

	subgraph cluster_two {
		b;
	}

	a -> b [ltail=cluster_one lhead=cluster_two];
}
\end{dot2tex}

This currently doesn't generate edge between two clusters, instead it generates edge between a and b