When searching for records on same field Odoo joins multiple queries
with OR. For example:

- Perform a search for customer "John" on field Name
- Odoo displays customers containing "John"
- Search for "Smith" on same field Name
- Odoo displays customers containing "John" OR "Smith"

With this module installed you can press Shift key before searching for
"Smith" and Odoo finds customers containing "John" AND "Smith"