when i delete a box or a arrow. the deleted event is firing, but deleting event is not firing.

what's the matter?

the code is :
1.
fc.BoxDeleting+=new MindFusion.Diagramming.WinForms.BoxConfirmation(fc_BoxDeleting);
fc.BoxDeleted+=new MindFusion.Diagramming.WinForms.BoxEvent(fc_BoxDeleted);

2.
void fc_BoxDeleted(object sender, MindFusion.Diagramming.WinForms.BoxEventArgs e)
  {MessageBox.Show("Box deleted"); }

void fc_BoxDeleting(object sender, MindFusion.Diagramming.WinForms.BoxConfirmArgs e)  {MessageBox.Show("Box deleting");  }

3.
fc.DeleteObject(flowChart1.ActiveObject);