method insert_line ?line ?(fgcolor="Black") ?(bgcolor="White") s =
let _ = wlist#append
[ (match line with None -> "" | Some n -> string_of_int n) ;
s
]
in
let _ = wlist#set_row
~foreground: (`NAME fgcolor)
~background: (`NAME bgcolor)
(* ~style: style*)
(wlist#rows -1)
in
()