method activate : unit =
w#set_style_property "width"
( obj >>> get "offsetWidth" >>> as_int >>> px_string ) ;
w#set_style_property "height"
( obj >>> get "offsetHeight" >>> as_int >>> px_string ) ;
if not activated
then (
body#obj >>> Dragg_n_drop_move.bind (fun (x,y) -> self#move (x,y)) ;
body#add_common (w :> common) ;
)