Sale Fiscal Position Update Button

When the sale order is in draft/sent state, you can change the fiscal position and click on a button Update Tax to update the taxes on all the sale order lines which have a product (if a sale order line doesn't have a product, it won't work and the user will have an error message).

This module is an alternative to the module sale_fiscal_position_update from the sale-wkfl OCA branch, which works with an on_change. It is particularly usefull when a country updates it's VAT rates and the salesman want to update their quote and have the new VAT rates in one click.