.rickshaw_graph .detail .item.active from detail.css would benefit by adding 'width: auto; height:auto;' to auto-size the detail tooltip on graph mouse hover. In it's current form, the tooltip doesn't get auto-sized when using a relative/percentage based layout.
In Chapter 5. Schema and Data Modeling first there is paragraph:
The default cardinality setting is SINGLE. Note, that property keys used on edges and properties have cardinality SINGLE. Attaching multiple values for a single key on an edge or property is not supported.