In a mugl file, if the column id attribute has a space, eg: "Rel. Humidity", the graph fails to load with the error:
Uncaught TypeError: Cannot read property 'columnIdToDataVariable' of undefined
Problem has recently arisen as the graph still loads on Multigraph.org in version 5.1.1.
Graph in question breaking on newer builds of Multigraph: http://multigraph.org/examples/?graph=precip_forecast