Add OR conditions to OpenERP filters with "Advanced Search"

OpenERP conditions in filters are joined with an AND operator.
But it's possible to add conditions with OR filters using an Advanced Search: if multiple conditions are set inside an Advanced Search, they will be joined with an OR operator.

For example, in Sales » Customers, to filter only Companies from either France or Belgium:

• Open the filter dropdown and select [Company] from the default filters.
• Add an Advanced Filter with [Country is equal to France +or+ Country is equal to Belgium].