Dropdown creation using GoJS

How can a dropdown selection box be created using GoJS, for selection a value from the available set of values as shown in below snapshot (in red box)

image

Initial value = Default
Other options = [“One”, “Two”, “Three”, “Four”]

I have tried using this code (for creating dropdown), but not getting how to create a drop down with selection items - “One”, “Two”, “Three”, “Four”:

$(go.Panel,"Horizontal",    
	$(go.Panel,"Auto",																	
		$(go.Shape,{fill : "white",height:27, width : 100}),
		$(go.TextBlock,
			{
				name : "CURRENT_DROPDOWN_VALUE",
				editable : true,
				text : "Default",
				margin : new go.Margin(5),
			}
          )
     ),

    $("Button", {height : 27,width : 20},
		$(go.Shape,"TriangleDown",{height : 4,width : 6}),
		{
           // click : function(e,obj) {
               // var node = obj.part;
               // e.diagram.startTransaction("Selecting Value");
               // var currentVal = node.findObject("CURRENT_LAYOUT_VALUE").text;

               //	** logic for getting new selection value will come here **
               // update node.findObject("CURRENT_LAYOUT_VALUE").text value
               // currentVal will now get new selection value
               //   currentVal = node.findObject("CURRENT_LAYOUT_VALUE").text;
               // e.diagram.commitTransaction("Selected Valuer");
           // }
          }
    )
)

An example is in Text Editing Examples.