在数据表窗体内双击事件弹出一个窗体,有句代码不知何意?

代码是这样的:

private sub form_load()

 dim ctr as control

 for each ctr in me.controls

 if ctr.section =acDetail and (typeof ctr is textbox) or (typeof ctr is combobox) or (typeof ctr is checkbox) then

  ctr.onDBClick = "allDBClick()"

 end if

 next

end sub

private function allDBClick()

 docmd.openForm " frm_入库单",acnormal,,"ID= "& Me.ID & ""

End function

请问一下:ctr.section =acDetail 这个代码是什么意思?敬请老师们给予解答.在此谢谢了.