Thingworx 9.0.4
I have a mashup that retrieves data via a service. The data is then bound to a contained mashup with the appropriate datashape for the mashup property. This mashup has a line chart and the mashup data property is bound to this line chart. The data is displayed without issue but the legend will not appear. I have ensured the "hide legend" checkbox is unchecked. When I did not have the contained mashup, I believe the legend was working.