Dear Odooers,

I want to add a search panel on below list view. With xml code below, I saw the ERROR as shown in the few lines at the bottom. Could someone please advise where I missed and did wrong? 

This field ( ) is a custom added field and can be seen in the tree view as shown. Why can't it be converted to SQL?

In Search bar, I can see "Product Category" in Filter but not in "Group By". Why?

Thank you very much for enlightening me.

>

The code is 

   
   purchase.purchase.order.view.search.inherit   
   purchase.order   
    
           
  	​	​
          
            
          
        
      
     

ERROR message: 

odoo\models.py", line 2810, in _field_to_sql

    raise ValueError(f"Cannot convert field {field} to SQL")

ValueError: Cannot convert field purchase.order.categ_id to SQL