When you create an action to open a view in Odoo (ir.actions.act_window) there is a set of fields you can use to customize the way in which the views are shown.
There is a couple of fields, usage and filter, that I don't understand very well. The field usage has the following comment:
Used to filter menu and home actions from the user form.
But actually I've only find one action using it in the whole code, an action which gives it the value menu:
<field name="usage">menu</field>
There are more window actions which use the boolean field filter, but I cannot get what it does.
Does anyone know what are these fields for and which values accepts usage?