Mouse-over node IDs are confusing with redundant nodes removed

[jeizenga]

Removing the redundant nodes gives it a cleaner look, but the way it presents the node IDs is confusing. I believe the mouse-over only shows the first node ID. I spent a while confused about this because I thought there were missing nodes in the visualization. Perhaps it would be better to make the mouse-over give a list of IDs, or maybe an ID range?