How do you change the fill color for a Plot Area?
This is similar to other fill type properties on the chart. Unfortunately the member list for the PlotArea is not including the members of its base ChartAreaBase; we're looking into addressing that. Here's an example of setting the fill for the plotArea.
var plotColor = new $.ig.excel.WorkbookColorInfo("#DDDDDD");
var plotFill = new $.ig.excel.ChartSolidFill(plotColor);
Let us know if you need any further assistance.