mbostock/d3 — pull request #758 by Nathanaela (2012-08-10 15:42:53+00:00)
Title: Issue with visulizations using the packtree layout parents having only one child are obscured.

If you use the http://mbostock.github.com/d3/ex/pack.html chart (or any other visualization based the packtree layout); and your parent circle only has one child; the parent is obscured by the child as the calculation makes the parent.size = child.size. Not sure if this is the best solution; but added code to make parent.size = child.size * 1.5; in the event the parent only has one child. Which causes the parent to be visible if it only has one child.