It looks as though the truncation of labels is done by the eCharts code, not the ui-chart widget. So even if we could mislead eCharts about the true width of the widget, it would probably still truncate the labels.
There is an example in the echarts docs which implies you can reduce the space allocated to the pie.
I have no idea how the dashboard invokes eCharts, but this looks related to what Colin said above re msg.ui_update. Can it be that 100% is the default and we could supply a different value?
Hopefully when the next dash board release is published we will get a clearer idea.
Thanks for your efforts @Colin !
