Add sequence field with handle in tree view

addons/delivery/delivery_view.xml

@@ -209,6 +209,7 @@
             <field name="model">delivery.grid.line</field>
             <field name="arch" type="xml">
                 <tree string="Grid Lines">
+                    <field name="sequence" widget="handle" />
                     <field name="name"/>
                     <field name="type"/>
                     <field name="operator"/>