Is it possible to add some CSS properties like box-shadow to the node only while it is being dragged from the palette till before it is dropped onto the canvas? If possible please redirect me to a sample.
Try this Binding on your Node template(s):
new go.Binding("isShadowed", "layerName", function(l) { return l === "Tool"; }).ofObject(),
BTW, please note that one cannot apply any CSS properties to any GraphObject.
Thanks. That helped.