private void drag_lbl_PreviewMouseUp(object sender, MouseButtonEventArgs e) { dragPoint = null; drag_lbl.RemoveHandler(Canvas.MouseMoveEvent, new MouseEventHandler(mouse_move)); drag_via_me.RemoveHandler(Label.MouseEnterEvent, new MouseEventHandler(mouse_enter)); drag_target.RemoveHandler(Label.MouseEnterEvent, new MouseEventHandler(mouse_enter)); }