I try to define the preferences of a firefox extensions with a

If I understand the doc correctly that should be possible without
having to add (build the listbox) or to store the values back in the
prefences with javascript.

I'm fiddling with


But I would be glad if someone could gave me an example of this,
since the listbox will have (say) between 1 and 10 lines, I wonder
how I could associate this lines with the prefences ?
Thanks for any help