White edges on panel shadow


I’m trying to round the shape of a group with some panels inside. That group is shadowed but in the outside shadow are appearing some white triangles on the edges…How can I get rid of them?
Here’s the picture:

and here’s my code:

          $(go.Node, "Auto",
            	isTreeExpanded: true,
                minLocation: new go.Point(NaN, NaN),  // not allow movement
                maxLocation: new go.Point(NaN, NaN),
                deletable: false
            new go.Binding("location", "loc", go.Point.parse).makeTwoWay(go.Point.stringify),
    			contextMenu: myContextMenu
              { fill: "#EEEEEE" }),
            // the content consists of a header and a list of items
            $(go.Panel, "Vertical",
              // this is the header for the whole node
              $(go.Panel, "Auto",
            	  stretch: go.GraphObject.Horizontal, 
      		  	  portId: "totale",
      		      fromSpot: go.Spot.Right,
	    		  toSpot: go.Spot.Left,
      		      fromLinkable: true,
    		      toLinkable: true,
  	              mouseEnter: function(e, obj) {  // the PORT argument will be this Panel
	                var shp = obj.panel.findObject("hover-screenshot-panel");
	                shp.fill = "#FF0000";
  	              mouseLeave: function(e, obj) {
  	                var shp = obj.panel.findObject("hover-screenshot-panel");
	                shp.fill = "#AF5555";
            	},  // as wide as the whole node
                $(go.Shape, "Rectangle",
                  	fill: "#AF5555", 
                  	stroke: null, 
                  	minSize: new go.Size(150, 10),
                  	name: "hover-screenshot-panel",
        		    background: "transparent"
      			  { source: imgpth+"enter_class.png",
      				column: 0,
      				background: "transparent", 
      				width: 20, 
      				height: 20,
      				alignment: go.Spot.TopLeft
                    alignment: go.Spot.Center,
                	column: 1, 
                    margin: new go.Margin(3, 5, 3, 10),
                    stroke: "white",
                    textAlign: "center",
                    font: "bold 10pt sans-serif"
                  new go.Binding("text", "cname")                  
                $("PanelExpanderButton", "TABLE",  
                	column: 2, 
   			        alignment: go.Spot.TopRight 
             $(go.Panel, "Table",
                  name: "TABLE",
                  padding: 2,
                  minSize: new go.Size(140, 10),
                  defaultStretch: go.GraphObject.Horizontal,
                  itemTemplate: fieldTemplate,
                  visible: false,
                new go.Binding("itemArray", "fields")
              ) // end Table Panel of items
            )  // end Vertical Panel
          ));  // end Node
        $(go.Group, "Auto",
            background: "white",
            handlesDragDropForMembers: true,
            // Groups containing Groups lay out their members horizontally
                  wrappingColumn: 1, 
                  wrappingWidth: Infinity, 
                  alignment: go.GridLayout.Position,
                  cellSize: new go.Size(1, 1), spacing: new go.Size(4, 4)
            isShadowed: true,
            shadowColor: "grey",
            shadowOffset: new go.Point(4,4)
		  { contextMenu: myContextMenu },
          new go.Binding("location", "loc", go.Point.parse).makeTwoWay(go.Point.stringify),
          $(go.Shape, "RoundedRectangle",
        	  fill: "white", 
        	  stroke: "#000000", 
        	  strokeWidth: 2
          $(go.Panel, "Vertical",  // title above Placeholder
            $(go.Panel, "Horizontal",  // button next to TextBlock
              { stretch: go.GraphObject.Horizontal, background: "#AF0000" },
                { alignment: go.Spot.Right, margin: 5 }),
                    alignment: go.Spot.Center,
                    margin: 3,
                    stroke: "white",
                    textAlign: "center",
                    font: "bold 10pt sans-serif"
                new go.Binding("text", "key").makeTwoWay())
            ),  // end Horizontal Panel
              { padding: 5, alignment: go.Spot.TopLeft })
          )  // end Vertical Panel
        ));  // end Group and call to add to template Map

Pls Help

Don’t set the background to “white”.

Ok, I commented out “background: white”, and now it appears this way:

I can see shadow thru the rounded rectangle shape of the group…no way to make the background of the group not transparent?

Set the fill of the “RoundedRectangle” Shape.

Thank you!