Add optional column on tree view

issue10989
review374321002

view/carrier_selection_list.xml

@@ -3,11 +3,11 @@
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 <data>
     <xpath expr="/tree/field[@name='from_country']" position="after">
-        <field name="from_subdivision"/>
-        <field name="from_postal_code"/>
+        <field name="from_subdivision" optional="1"/>
+        <field name="from_postal_code" optional="1"/>
     </xpath>
     <xpath expr="/tree/field[@name='to_country']" position="after">
-        <field name="to_subdivision"/>
-        <field name="to_postal_code"/>
+        <field name="to_subdivision" optional="1"/>
+        <field name="to_postal_code" optional="1"/>
     </xpath>
 </data>