Rails - Apr 2005 - destroy list item with dependents problem

I have a todo list where each todo item can has_many tc_items.

class Todo < ActiveRecord::Base
    acts_as_list
    has_many :tc_items, :class_name => "TcItem", :dependent =>
true
    has_one :where, :class_name => "TcItem", :conditions =>
"ckey=''where''"
end

My todo controller destroy action can either get the position column to
update correctly or delete the dependent tc_items correctly. But not
both - which is what I want.

1) If I want position column to update correctly (but dependents remain)

    Todo.find(@params[''id'']).remove_from_list
    Todo.delete(@params[''id''])

Destroying 3rd rec gives correct positions:-
1,2,3,4,5
1,2,  3,4

2) If I want to delete dependents correctly (but positions screwed up)

    Todo.find(@params[''id'']).remove_from_list
    Todo.destroy(@params[''id''])

Destroying 3rd rec:-
1,2,3,4,5
1,2,  3,3

3) Looking at the AR list.rb code I see 

    after_destroy  :remove_from_list

which suggests (I am a Ruby Nooby) that all I should need to do is
destroy and then remove_from_list should be called automatically. 

    Todo.destroy(@params[''id''])

Destroying 3rd rec:-
1,2,3,4,5
1,2,  3,3

So yes, destroy does seem to be messing about with the position column
but it is screwing up.

4) If I just do remove_from_list :-

    Todo.find(@params[''id'']).remove_from_list

Then I get (as expected)

Destroying 3rd rec:-
1,2,3,4,5
1,2,3,3,4

So I cant find a working combination of the above. Any help appreciated.

Peter