[求救]关于Delphi中控件的拖放（初次使用Delphi，望高人指点）[14]

4.  drag and drop of work order for production planning

    user may drag and drop the rectangle box from a day to the other.  then, the

    graphical display shall be refreshed accordingly showing the newly summed

    loading.

    when user click a [save] button, the revised expected starting date of work

    orders shall be updated accordingly.  before that, user's work is only a

    worksheet draft copy.  if user is going to exit the program without saving,