Google Maps Polygon editing - get latlng position on mouseup
===

I am trying to write a simple snapping function for editing a polygon in Google Maps v3.9


I have several polygons on the map, which can be made editable one at a time.
When one is made editable, I also add a listener to it, to trigger when a vertex has been dragged. 

As there is no drag event for `google.maps.Polygon`, I add a `mousedown` listener, which checks if a vertex is beneath the cursor, and if so adds a `mouseup` listener.
The code within this `mouseup` listener checks against the vertices of all other polygons, and updates the dragging vertex if a close match is found.

This works well, except for one problem.  The check is performed using the `latLng` property of the `PolyMouseEvent` returned by the `mouseup` listener.  This property points to the location of the vertex *before* it was dragged, and I can't find a way to reference the vertex in its new position.


    dragListener = google.maps.event.addListener( poly1, "mousedown", function( dragData ) {

        // if dragging a vertex
        if ( dragData.vertex != null ) {

            // perform snap on mouseup
            snapListener = google.maps.event.addListener( poly1, "mouseup", function( mouseData ) {
                var editingVertex = mouseData.vertex;
                var draggedLatLng = mouseData.latLng;

                // code here to compare draggedLatLng with latLng of editingVertex
                // and perform snap, which seems to work fine as is...
            }
        }
    }
                


