Added Pos methods to DisplayDrag{Enter,Move}Event.

ui/event.go

@@ -20,12 +20,12 @@ type DisplayDragLeaveEvent struct {
 	EventBase
 }
 
-type DisplayDragMoveEnter struct {
+type DisplayDragMoveEvent struct {
 	EventBase
 	X, Y float32
 }
 
-func (e DisplayDragMoveEnter) Pos() geom.PointF32 {
+func (e DisplayDragMoveEvent) Pos() geom.PointF32 {
 	return geom.PtF32(e.X, e.Y)
 }