There were several issues with this widget, and the way the model
handles its requests (mainly the removal of values).
It crashed for instance on the product form view when the user
updated the routes field (field route_ids in tab inventory).
The readonly attribute of a field in its description can be
overriden in the views (e.g. with modifiers). So readonly fields
may actually be edited from views in which there is a modifiers
on their node overriding the default value.
Before this rev., readonly fields couldn't be saved, even if they
could be edited from views (with such modifiers).
For instance, it wasn't possible to change the value of the
partner_id field in a draft sale_order.
In a form view, if a one2many list view contained a many2many
field (e.g. widget many2many_tags), the commands for the embedded
many2many weren't generated for newly created one2many subrecords,
so this field couldn't be saved.
Aaron Bohy