gistfile1.txt

        <!-- Opening task when double clicking on project -->
        <record id="dblc_proj" model="ir.actions.act_window">
            <field name="res_model">project.task</field>
            <field name="name">Project's tasks</field>
            <field name="view_type">form</field>
            <field name="view_mode">tree,form,calendar,graph,gantt,kanban</field>
            <field name="domain">[('project_id', 'child_of', [active_id])]</field>
            <field name="context">{'project_id':active_id, 'active_test':False}</field>
        </record>

        <record id="ir_project_task_open" model="ir.values">
            <field eval="'tree_but_open'" name="key2"/>
            <field eval="'project.project'" name="model"/>
            <field name="name">View project's tasks</field>
            <field eval="'ir.actions.act_window,'+str(dblc_proj)" name="value"/>
        </record>