When clicking on an action button, form view first saves then executes
the action. In doing so, it causes the o2m field to call
ListView#reload_content twice without waiting for the reloading to
end, generating a race condition in ListView.List#render_dataset.
As a result, the read_slice callback fills the list twice (once for
each #reload_content call), resulting in everything being duplicated.
Clear the content of the records collection before adding stuff.
note: collections should dedup on ids.
lp bug: https://launchpad.net/bugs/877965 fixed
bzr revid: xmo@openerp.com-20111025085112-q38q8m0k2mopwadg
Xavier Morel
b6a0874f4c