I strongly suggest to add
<field name="orderby">[expanded variables] </field>
to xml
which applies to the "visible" column content
Example
product_id should be sorted by the translated value of product_id.name
this would allow to sort the results in the selected language
I strongly suggest to add >[expanded variables] </field>
<field name="orderby"
to xml
which applies to the "visible" column content
Example
product_id should be sorted by the translated value of product_id.name
this would allow to sort the results in the selected language
similar to
<field name="groupby" ....