Robert,
Since Graphic extends the UIComponent i guess it is the Mouse Click. The only event registered with Graphic is "change" i don't see anything else.
1) I have a store graphic and i have attached a InfoWindow to the graphic.
2) A drivetime is drawn around this graphic.
3) On clicking the drivetime graphic i want to show the infowindow associated with the store graphic.
EDIT: map.infoWindow.show(graphic.geometry as MapPoint); does it. I don't have to fire any event to do this.