Multigraph will not initilize unless a height is set

[brian-may]

Creating a new multigraph will fail with the errorr: this.context(...) is undefined when no height is set on the target div. Additionally setting the height property in the multigraph function call does not work.

Fails:
http://pastebin.com/wg95sPQW

Works:
http://pastebin.com/cD59XvgY