FireMonkey - TListBox启用拖放

Question

我正在尝试在FireMonkey中的TListBox中启用TListBoxItems的拖放。它似乎有时会拖放，但有时它甚至不会进入事件处理程序

procedure TForm1.ListBox1DragChange(SourceItem, DestItem: TListBoxItem; var Allow: Boolean);
begin
  SourceItem.Index := DestItem.Index;
end;

我将DragMode设为dmManual

object ListBox1: TListBox
    Height = 200.000000000000000000
    Position.X = 224.000000000000000000
    Position.Y = 144.000000000000000000
    TabOrder = 1
    Width = 200.000000000000000000
    AllowDrag = True
    Items.Strings = (
      'First'
      'Second'
      'Third'
      'Fourth'
      'Fifth'
      'Sixth')
    DefaultItemStyles.ItemStyle = ''
    DefaultItemStyles.GroupHeaderStyle = ''
    DefaultItemStyles.GroupFooterStyle = ''
    OnDragChange = ListBox1DragChange
  end