Invisible fields receive focus in editable one2many lists

[Borja López Soilán (NeoPolus)]

When using the "new" button to add a record to a one2many widget in tree mode, the first record of the new tree line will receive the focus, even if that field is invisible. And even, using the Tab key, the focus goes through each of the visible and invisible fields, letting the user edit (blindly) the invisible ones! :

For example, this view (containing a one2many widget, that has three fields, one of the hidden ones used only to restrict the domain of the second field, and other of the hidden ones used to set the row colour) will receive focus on the invisible partner_id when creating a new record, and will give focus to state when using the tab key.
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                            <field name="children_list" context="{'partner_id': partner_id}">
                                <tree string="Children" editable="top" colors="blue:state=='draft';gray:state=='old'">
                                    <field name="partner_id" invisible="1"/>
                                    <field name="element_id" domain="[('partner_id','=',partner_id)]"/>
                                    <field name="state" invisible="1"/>
                                </tree>
                                <form string="Child">
                                    ...
                                </form>
                            </field>
                        </page>
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