How to find the panel location that is on a link

I have the code below,
I want to double click on the panel and find the panel location, (i want to open a special form at that place)
I use the diagramEvent to find the part
and tried to get the location from event.subject.part

is there a way to do it?

let link =new go.Link()
let panel = new Panel(Panel.Auto);
link.add(panel)

It might be easier to set the panel’s GraphObject.doubleClick event handler.

  panel.doubleClick = function(e, pan) {
    e.viewPoint  // returns the point of the double click
               // in the viewport, i.e. the HTMLDivElement
  };

But for any GraphObject:

    obj.diagram.transformDocToView(obj.getDocumentPoint(go.Spot.Center))

will return its center in viewport coordinates.