void HandlePhotoViewDragDataReceived (object sender, DragDataReceivedArgs args)
{
//Widget source = Gtk.Drag.GetSourceWidget (args.Context);
//Console.WriteLine ("Drag received {0}", source == null ? "null" : source.TypeName);
HandleAttachTagCommand (sender, null);
Gtk.Drag.Finish (args.Context, true, false, args.Time);
photo_view.View.GrabFocus ();
}
#endregion