project_task_views.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data>

        <record id="view_task_tree2" model="ir.ui.view">
            <field name="name">project.task.tree.inherit</field>
            <field name="model">project.task</field>
            <field name="inherit_id" ref="project.view_task_tree2"/>
            <field name="arch" type="xml">
                <field name="date_deadline" position="after">
                    <field name="duree_hr" sum="Durée"/>
                </field>
            </field>
        </record>

        <record id="view_task_form2" model="ir.ui.view">
            <field name="name">view.task.form2.form.inherit</field>
            <field name="model">project.task</field>
            <field name="inherit_id" ref="project.view_task_form2"/>
            <field name="arch" type="xml">
                <xpath expr="//notebook" position="before">
                    <group>
                        <field name="participant_ids" widget="one2many">
                            <tree string="Participants" editable="top">
                                <field name="porteur_id"/>
                                <field name="lastname"/>
                                <field name="firstname"/>
                                <field name="commune"/>
                                <field name="mobile"/>
                                <field name="fixe"/>
                                <field name="email" widget="email"/>
                                <field name="is_present"/>
                            </tree>
                        </field>
                    </group>
                </xpath>
                <xpath expr="//field[@name='user_id']" position="after">
                    <field name="formateur_id"/>
                </xpath>
                <xpath expr="//field[@name='date_deadline']" position="after">
                    <field name="duree_jr"/>
                    <field name="subtask_project_id" invisible="1" />
                    <field name="parent_id" invisible="1" />
                    <field name="partner_id" invisible="1" />
                </xpath>
                <xpath expr="//notebook/page[@name='description_page']" position="attributes">
                    <attribute name="invisible">1</attribute>
                </xpath>
                <xpath expr="//notebook/page[@name='extra_info']" position="attributes">
                    <attribute name="invisible">1</attribute>
                </xpath>
            </field>
        </record>

        <record id="quick_create_task_form" model="ir.ui.view">
            <field name="name">project.task.form.quick_create.inherit</field>
            <field name="model">project.task</field>
            <field name="inherit_id" ref="project.quick_create_task_form"/>
            <field name="arch" type="xml">
                <field name="user_id" position="replace">
                    <field name="date_deadline"/>
                </field>
            </field>
        </record>

    </data>
</odoo>