how to set treeview and drawarea in same position?

["chen.shengqi" <chen shengqi connet com tw>]

Dear sirs:
        I want to place a treeview in center of a drawingarea some time(treeview  is smaller than drawingarea 
) , but the container can only accept one object, How can I overcome this?  In windows, you can place as many 
object as you want in a container.
        thanks