method on_tab_destroy c new_c =
match self#tab_of_contents c with
None -> ()
| Some n ->
tabs <- List.filter
(fun (_,c2) -> id_of_contents c2 <> id_of_contents c) tabs;
nb#remove_page n;
match new_c, tabs with
None, []
| None, [_] -> self#destroy
| None, _ -> ()
| Some new_c, [] ->
on_destroy (Some new_c);
nb#destroy ()
| Some new_c, _ ->
self#add_tab (Some n) new_c