For some reason, a filter was made on the non-existing field 'categ_id'.
Result: crash crash boom.
<group expand="0" string="Group By">
<filter name="group_by_partner_id" string="Partner" context="{'group_by':'partner_id'}"/>
<filter string="Salesperson" context="{'group_by':'user_id'}"/>
- <filter string="Category of Product" name="category_product" context="{'group_by':'categ_id','residual_invisible':True}"/>
<filter string="Status" context="{'group_by':'state'}"/>
<separator/>
<filter string="Period" context="{'group_by':'period_id'}"/>