Before this revision,
it wasn't possible, in the form header,
to organize buttons in nodes.
If you attempted to do so, the buttons were not appearing.
e.g. for the below form
```xml
<form>
<header>
<button name="0"/>
<button name="1"/>
<div id="special_buttons">
<button name="2"/>
<button name="3"/>
</div>
</header>
</form>
```
Before this revision, the buttons 2 and 3 were not appearing.
Adding this possibility can allow simpler inheritage,
for instance by organizing buttons in sections and then
the inherited view can add buttons directly within the right section,
using a selector targetting the section.
It also allows to restrict a button to users having 2 groups.
e.g.
```xml
<button name="action_draft" position="after">
<div groups="sale.group_auto_done_setting">
<button name="action_done" type="object" string="Lock"
states="sale"
help="If the sale is locked, you can not modify it anymore. However, you will still be able to invoice or deliver." groups="sales_team.group_sale_manager"/>
<button name="action_unlock" type="object" string="Unlock"
states="done"
groups="sales_team.group_sale_manager"/>
</div>
</button>
```
If you want to restrict the button `action_done` to users
having both `sale.group_auto_done_setting` and `sales_team.group_sale_manager`,
you cannot put both groups on the same node,
because otherwise it's an OR connection, not an AND.
`groups="sale.group_auto_done_setting,sales_team.group_sale_manager"`
means
"users has `sale.group_auto_done_setting` or `sales_team.group_sale_manager`",
not AND.
So, the only possibility to restrict a button to two groups with an AND
connection is to restrict the button to a group and nest the button
inside a block restricted to the second group.
The above example is an actual example/need from the existing code.
But, as this possibility wasn't there before this revision,
they achieved the goal by using the `groups_id` feature:
```xml
<record id="view_sales_order_auto_done_setting" model="ir.ui.view">
<field name="name">sale.order.form</field>
<field name="model">sale.order</field>
<field name="inherit_id" ref="sale.view_order_form"/>
<field name="groups_id" eval="[(4, ref('sale.group_auto_done_setting'))]"/>
<field name="arch" type="xml">
<button name="action_draft" position="after">
<button name="action_done" type="object" string="Lock"
states="sale"
help="If the sale is locked, you can not modify it anymore. However, you will still be able to invoice or deliver." groups="sales_team.group_sale_manager"/>
<button name="action_unlock" type="object" string="Unlock"
states="done"
groups="sales_team.group_sale_manager"/>
</button>
</field>
</record>
```
So they had to use an inerited view for that purpose only to restrict
the button to two groups. It's a work-around.
It is much simpler to allow to have nested buttons in the header of the
form.
closesodoo/odoo#98551
Related: odoo/enterprise#30643
Related: odoo/upgrade#3812
Signed-off-by: Denis Ledoux (dle) <dle@odoo.com>
Denis Ledoux
43953c2a4d